Multi-Jurisdictional
Hazard Mitigation Plan Onslow County, NC
JULY 2015
Onslow County Town of Holly Ridge City of Jacksonville Town of North Topsail Beach Town of Richlands Town of Swansboro ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
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PREFACE
TO: The Citizens of Onslow County, the City of Jacksonville, and the Towns of Holly Ridge, North Topsail Beach, Richlands, and Swansboro. Mitigation is the cornerstone of emergency management. It is an ongoing effort to lessen the impact that hazards could have on people and property. Mitigation is defined as “sustained action that reduces or eliminates long-term risk to people and property from natural hazards and their effects”. It describes the continuing effort at the federal, state, local and individual levels to lessen the impact of hazards on our families, homes, communities, and economy. Through the application of mitigation measures, technologies, and an overall multi-jurisdictional team strategy, Onslow County and its five (5) municipalities will ensure that fewer of our citizens and their property become victims of natural hazards. Mitigation measures will continue to be applied to strengthen your home, local businesses, and industry through code enforcement, so that you family and belongings are better protected from hurricanes, floods, costal storms, fires, and other natural hazards. Mitigation technologies will continue to be used to strengthen critical infrastructure such as our schools, medical facilities, power and utility systems, emergency response organizations, and other vital service facilities to ensure continuity of government. Most importantly our mitigation strategy has been designated to reduce the loss of life and suffering that natural hazard events have the potential of causing during and in the aftermath of their impact on our communities. A fundamental premise of our hazard mitigation strategy is that dollars invested in mitigation today will significantly reduce the demand for future expenditures by reducing the extent of emergency response and recovery to the hazard; and repair and reconstruction of infrastructure following a disaster. This comprehensive multi-jurisdictional plan includes resources and information to assist county and municipal residents, public and private sector organizations, and others interested in participating in mitigation planning and implementation. The plan further provides a list of activities that may assist you in reducing the risk to future natural hazard events. Onslow County, its municipal elected officials, and emergency service organizations remain committed to your safety and the continued economic growth of our area. Thank you for your required support in this crucially important effort.
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Revisions
In order to maintain an acceptable level of multi-hazard preparedness, it is necessary to review and update this Emergency Operations Plan (EOP) on at least an annual basis. The Onslow County Department of Emergency Services is the lead agency on the EOP review, and shall coordinate all plan reviews / revision efforts. The Department of Emergency Services shall also be responsible for incorporating all changes to the plan. Such revisions will be prepared based upon the required annual review process or, as the result of periodic drills, tests, and/or functional exercise evaluations of the contents of this plan.
The "Record of Revisions" (Figure 1), is provided in this section to assist plan holders with documenting appropriate plan changes. As revisions are incorporated into this plan, each plan holder will be forwarded a revision package containing the following information:
1. Detailed instructions for inserting plan revisions.
2. The appropriate plan changes as page inserts or directed pen changes.
3. A summary of effective revisions to the plan referencing the section affected, the current revision number, and date.
Revision Date Section/Page Reference Name Department
2012-01 08/10/2012 Various – grammatical and formatting changes Stacie Miles OCES Various – census and data updates. Removal of 2012-02 08/12/2012 Stacie Miles OCES critical facility tables. 5 Year FEMA Update. Major changes throughout. 2014-01 08/01/2014 Stacie Miles OCES New Format
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Multi-Jurisdictional Hazard Mitigation Plan
1. Table of Contents 1. INTRODUCTION ...... 1
1.1. Background ...... 1
1.2. Purpose...... 2
1.3. Scope...... 2
1.4. Authority ...... 4
2. THE PLANNING PROCESS ...... 1
2.1. Overview of Hazard Mitigation Planning...... 1
2.2. History of Hazard Mitigation Planning in Onslow County ...... 2
2.3. Preparing the 2015 Plan ...... 2
2.4. The Planning Team ...... 3
2.5. Community Involvement and Input ...... 5
3. COMMUNITY PROFILE ...... 1
3.1. Geography and Environment ...... 1
3.2. Population and Demographics ...... 2
3.3. Housing, Infrastructure, and Land Use ...... 2
3.4. Employment and Industry ...... 3
3.5. Disaster Declarations ...... 4
4. HAZARD IDENTIFICATION AND ANALYSIS ...... 1
4.1. Study Area ...... 2
4.2. Drought and Heat Wave ...... 3
4.3. Severe Thunderstorm and Hail ...... 8
x ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
4.4. Hurricane & Coastal Storm (includes Nor’easter) ...... 18
4.5. Tornado ...... 26
4.6. Winter Storm ...... 32
4.7. Earthquake ...... 35
4.8. Landslide and Sinkhole ...... 38
4.9. Tsunami ...... 42
4.10. Coastal and Riverine Erosion ...... 44
4.11. Dam and Levee Failure ...... 47
4.12. Flooding ...... 49
4.13. Storm Surge ...... 56
4.14. Wildfire ...... 59
4.15. Conclusions on Hazard Identification and Analysis ...... 63
5. VULNERABILITY ASSESMENT ...... 1
5.1. METHODOLOGY...... 2
5.2. Study Area Definition ...... 6
5.3. Drought & Heat wave ...... 14
5.4. Severe Thunderstorm & Hail ...... 15
5.5. Hurricanes and Coastal Storms (Includes Nor’easters) ...... 16
5.6. Tornado ...... 17
5.7. Winter Storm ...... 18
5.8. Earthquake ...... 19
5.9. Landslide and Sinkhole ...... 20
5.10. Tsunami ...... 21
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5.11. Coastal & Riverine Erosion ...... 22
5.12. Dam & Levee Failure...... 23
5.13. Flooding ...... 24
5.14. Storm Surge ...... 29
5.15. Wildfire ...... 31
5.16. Conclusions On Hazard Vulnerability ...... 33
6. CAPABILITY ASSESSMENT ...... 1
6.1. What is a Capability Assessment ...... 1
6.2. Capability Assessment Findings ...... 1
6.3. Conclusions on Local Capability ...... 12
7. MITIGATION STRATEGY ...... 1
7.1. Introduction ...... 1
7.2. Community Goals and Mitigation Objectives ...... 2
7.3. Identification and Analysis of Mitigation Techniques ...... 4
8. MITIGATION ACTION PLAN ...... 1
9. PLAN MAINTENANCE ...... 1
9.1. Implementation ...... 1
9.2. Monitoring, Evaluating and Updating the Plan ...... 1
9.3. Incorporation into Other Planning Mechanisms ...... 5
9.4. Continued Public Involvement ...... 5
9.5. Plan Adoptions ...... 6
9.5.1. Adoption Resolutions ...... 7
APPENDIX A: PLANNING DOCUMENTATION ...... 1
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APPENDIX B: FEMA LOCAL MITIGATION PLAN REVIEW ...... 1
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1. INTRODUCTION
This section provides a general introduction to the Brunswick County Multi‐Jurisdictional Hazard Mitigation Plan. It consists of the following four subsections:
1.1 Background 1.2 Purpose 1.3 Scope 1.4 Authority
1.1.Background
Natural hazards are a part of the world around us. Their occurrence is natural and inevitable, and there is little we can do to control their force and intensity. However, through hazard mitigation planning, we can control the results by minimizing the impact natural hazard events have on our environment, and we can influence such events from resulting in disasters.
Onslow County, with a population of approximately 185,220 (US Census 2013 estimates), is located in southeastern North Carolina on the Atlantic Coast. It is a region particularly vulnerable to the effects of a wide range of natural hazards that threaten the life and safety of County and municipal residents, and have the potential to damage or destroy both public and private property and disrupt the Hazard Mitigation local economy and overall quality of life. The County government, its residents Any sustained action taken to and businesses have, in past years suffered disaster losses resulting in severe reduce or eliminate long- injuries and loss of life, and economic losses into the millions of dollars. term risk to people and their property from hazards. Beginning in the mid-1990’s, Onslow County established a firm commitment to reduce the potential for future disaster losses. Following a destructive series of hurricanes and coastal storms, Onslow County applied for and received funding to mitigate both public and private property against future storm events. These mitigation projects have already proven themselves very effective.
While the threat from hazards will never be fully eliminated, there is much that we can do to lessen their impact to our community and our citizens. The goal of hazard mitigation is to help prevent events from becoming disasters by instituting policies, procedures and education on methods of risk reduction. There are two primary forms of mitigation: structural such as strengthening of buildings and non-structural such as floodplain management and land use policies. A primary principle of hazard mitigation involves addressing hazard vulnerabilities that exist today as well as planning for hazards that may exist in the future.
Key to the life of the plan is that the communities develop, adopt and update the plan on a regular basis. The plan should be local in nature to ensure it is relevant to the hazards and vulnerabilities to that community. The plan should be a broad vision of guiding principles to help reduce risk and provide a format to propose specific actions that will work to eliminate or reduce the identified vulnerabilities.
Disaster Mitigation Act of 2000 and the National Flood Insurance Reform Act of 2004
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The United States Congress passed the Disaster Mitigation Act of 2000 (DMA 2000) in an effort to support and enhance the original Robert T Stafford Act. The DMA 2000 was an opportunity to revitalize approaches to mitigation planning. Specifically Section 322 of the DMA 2000 addresses the need for state and local governments to closely coordinate mitigation planning activities and makes preparation of multi-hazard mitigation plans a precondition for receiving FEMA mitigation project grants. These grants can include the Hazard Mitigation Grant Program (HMGP) and the Pre-Disaster Mitigation (PDM) program. Meeting the requirements of DMA 2000 will help ensure that communities are available to apply for and potentially receive federal grant funding both before and after a disaster.
The Flood Insurance Reform Act of 2004 also created two new grant programs and modified an existing program designed to assist communities. The Act developed the Severe Repetitive Loss (SRL) program and the Repetitive Flood Claim (RFC) program and modified the Flood Mitigation Assistance (FMA) program. The Act imposed the requirement of a FEMA approved hazard mitigation plan to be eligible for funding under these programs.
1.2.Purpose
The purpose of the OC MJ-HMP is to establish and promote a sound public policy designed to protect citizens, private property, critical infrastructure, and the environment from natural hazards.
This will be achieved by increasing public awareness, documenting the resources for risk reduction and loss- prevention, and identifying activities to guide Onslow County and its municipalities towards building a safer, more sustainable community.
In that, regard the OC MJ-HMP benefits the citizens of Onslow County and its municipalities by:
Protect life and property by reducing the potential for future damages and economic losses that result from natural hazards Demonstrate a firm local government commitment to hazard mitigation principles. Comply with both State and Federal legislative requirements for local hazard mitigation plans. Qualify for grant funding in both the pre-disaster and post-disaster environments Support Continuity of Government Operations, maintain critical facilities and protect infrastructure. Speed recovery and redevelopment following future disaster events. Provide for favorable political consequences for government action. Limit legal liability of government and public officials.
1.3.Scope
The original Onslow County Multi-Jurisdictional Plan was developed in 2004 and under the first FEMA update and review in 2009. The plan is reviewed and updated as needed on an annual basis with a full review and FEMA submission every five years. The OC MJ-HMP includes those hazards as prescribed by current FEMA and NCEM guidance. Other hazards will be considered, but are not required to be fully addressed within this Plan
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The geographic scope (graphic 1.1) of the OC MJ-HMP includes all unincorporated areas of Onslow County, and all the incorporated areas of its five (5) municipalities, namely; the City of Jacksonville, and the Towns of Holly Ridge, North Topsail Beach, Richlands, and Swansboro. It does not include any State, Federal, or military facility owned lands or infrastructure within Onslow County
Graphic 1.1 Onslow County, NC and Municipalities
In practice, the functional scope of our mitigation strategy may take on many forms. It will involve specific actions such as:
Promoting sound land use planning based on known hazards. Developing, adopting, and enforcing effective building codes and standards. Using fire-retardant materials in new construction. Installing hurricane straps more securely to attach a structure's roof to its walls and foundation.
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Developing and implementing mitigations plans for individual homes and businesses to reduce susceptibility to hazards. Relocating or elevating structures out of the floodplains. Buying flood insurance to protect against loss of belongings. To achieve the stated purpose, this plan addresses the following major sections: Hazard identification and analysis. Probability of hazard events. Vulnerability to hazards. Mitigation capability. Acceptability assessment. Identification of goals, objectives, and policies. Implementation, monitoring, and evaluation and update of the plan once it has been adopted.
1.4.Authority
The Onslow County Multi-Jurisdictional Hazard Mitigation Plan has been developed in accordance to all state and federal rules and regulation governing local hazard mitigation and has been approved and adopted by all participating jurisdictions and partners in accordance with their respective procedures. The plan is monitored and revised to maintain compliance with the following rules, provisions and legislation:
Section 322, Mitigation Planning, Robert T. Stafford Disaster Relief and Emergency Assistance Act, as enacted by Section 104 of the Disaster Mitigation Act of 2000
FEMA Interim Final Rule published in the Federal Register on February 26, 2002, at 44 CFR Part 201
National Flood Insurance Act of 1968, as amended 42 U.S.C. 2001 et seq
NC Senate Bill 300
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2. THE PLANNING PROCESS
This section of the plan describes the mitigation planning process undertaken by Onslow County and the participating jurisdictions in preparation of the Hazard Mitigation Plan.
2.1 Overview of Hazard Mitigation Planning
2.2 History of Hazard Mitigation Planning in Onslow County
2.3 Preparing the 2015 Plan
2.4 The Planning Team
2.5 Community Involvement and Input
2.1.Overview of Hazard Mitigation Planning
Mitigation planning is most effective when it is based on a comprehensive, long-term plan that is developed before a disaster occurs. The purpose of mitigation planning is to identify local policies and actions that can be implemented over the long term to reduce risk and future losses from hazards. Local hazard mitigation planning ELEMENT A1 should be community oriented in assessing risk and vulnerability and 44 CFR Part 201.6(c)(1): The practices to best minimize or manage those risks. plan shall document the planning process used to To ensure a functioning plan each identified mitigation action should be develop the plan, including assigned to a specific individual, department or agency along with target how it was prepared, who completion dates or timelines. The plan should also establish a maintenance was involved in the process, schedule to will ensure it remains current and dynamic and can be and how the public was incorporated into routine local decision making. involved.
Benefits of mitigation planning include:
Identifying actions for risk reduction Focusing resources on the greatest risks and vulnerabilities Building partnerships Increasing education and awareness through threats and hazards, as well as their risks Communicating priorities to State and Federal officials Aligning risk reduction with other community objectives
The core assumption of hazard mitigation planning is that the investments made before a hazard event will significantly reduce the demand for post disaster assistance by lessening the need for emergency response, repair, recover and reconstruction.
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2.2.History of Hazard Mitigation Planning in Onslow County
In February 2004, Onslow County received a federally funded Hazard Mitigation Plan Grant through the Hazard Mitigation Section, of the North Carolina Emergency Management (NCEM), to prepare a County multi- jurisdictional hazard mitigation plan. This grant was funded with Federal Emergency Management Agency (FEMA) 404 funds pursuant to the Robert T. Stafford Disaster Relief Act, and the Disaster Mitigation Act of 2000 (DMA 2000). The County was required to provide a 25% match that was met by an in-kind contribution of employee hours by the County Emergency Services, Plans, and IT (GIS) Departments.
Onslow County contracted with a consultant to facilitate and guide the mitigation planning process. The consultant became the central repository of all information gathered in the process, and assisted in information analysis, and compiling the information and recommendations into the Onslow County Multi-Jurisdictional Hazard Mitigation Plan (OC MJ-HMP) in compliance with those guidelines recommended by the Federal Emergency Management Agency. A Planning Team, led by the consultant, was developed and met throughout 2003 to develop and review the plan. Two public hearings, held at County Commissioners meetings, were held allowing the public to have involvement, input and information on the planning process and the final plan. The first meeting was held on January 30, 2004 and the second meeting was held on January 30, 2005.
2.3.Preparing the 2015 Plan
Hazard mitigation plans are required to be updated and reviewed by FEMA on a five year cycle to remain eligible for grant funding and disaster assistance. Starting in February of 2014 Onslow County Emergency Services and the City/Town representatives began the process of the 5 year update. The Onslow County Hazard Mitigation Plan Update Advisory Committee was comprised of representatives from Onslow County government, Holly Ridge, the City of Jacksonville, North Topsail Beach, Richlands and Swansboro. The Committee met on February 13, 2014 for its first meeting to discuss what actions needed to be followed to adhere to state guidelines. The Update Advisory Committee set forth a timeline to include several follow-up meetings and scheduled public hearings.
Representatives then returned to their respective jurisdictions to work within their city/town governments at identifying pertinent changes to their annexes. The respective jurisdictions completed necessary research and documentation. Each jurisdiction utilized the Local Hazard Mitigation Plan Update Materials and Supplemental Information as provided by NCEM Recovery Division. Other reference materials are identified in the Section titled “Keeping Natural Hazards from Becoming Disasters.” Jurisdictions also consulted with State and Local offices to assist in changes and updates in information and flood data.
The update resulted in many small changes throughout the document that include minor numerical changes, additions of sections that pertain to the 2015 update and complete revisions of worksheets. A summary of the major changes can be found below:
In September 2014, the updated OC MJ-HMP was then approved as written by the OC Board of Commissioners contingent upon approval by North Carolina Emergency Management (NCEM) and the Federal Emergency Management Agency (FEMA). Upon approval by both NCEM and FEMA the OC Board of Commissioners formally adopted the plan and would officially implement it for the next 5 year period.
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2.4.The Planning Team
Onslow County has appointed a County Hazard Mitigation Officer to coordinate hazard mitigation planning activities in the County. Each of the municipalities in the County has also appointed a City/ Town Hazard Mitigation Officer to coordinate hazard mitigation planning activities in their jurisdiction.
The Onslow County Hazard Mitigation Officer, in coordination with the surrounding City/ Town Hazard Mitigation Officers, has formed a County (Multi-Jurisdictional) Hazard Mitigation Plan (HMP) Advisory Committee that is comprised of key representatives from each of the participating jurisdictions which includes Onslow County, the City of Jacksonville, and the Towns of Holly Ridge, North Topsail Beach, Richlands, and Swansboro. Each of the municipalities has also formed a City/ Town HMP Advisory Committee in their respective jurisdictions.
Members of the County and City/ Town HMP Advisory Committees provide a multi-disciplined local capability to identify mitigation opportunities and implement mitigation measures in either a pre-incident or a post- incident situation.
The County and City/ Town HMP Advisory Committees are not a standing organization of rigid membership and regular duties, but rather one of flexible membership whose makeup and duties are dependent upon the particular mitigation activity under consideration. This flexibility allows the County or City/ Town Hazard Mitigation Officers to tailor the group to meet the unique situation in their jurisdiction while ensuring the involvement of appropriate individuals from the community.
The Onslow County Emergency Services Department has sent a representative to Raleigh to attend NCEM training on the Hazard Mitigation Update process. The following table identifies those people chosen to represent the County and the City/Towns during the 2015 OC MJ-HMP update process.
Table 2.1 Mitigation Advisory Committee Members Name Jurisdiction David Cotton Onslow County
Norman Bryson Onslow County
Stacie Miles Onslow County Andrew Jaspers Onslow County Alan Fernandez Onslow County Ben Warren Onslow County Patricia Pike Onslow County Spencer Lee City of Jacksonville Heather Reynolds Town of Holly Ridge
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Deborah Hill Town of North Topsail Beach Gregg Whitehead Town of Richlands Jennifer Holland Town of Swansboro Bob Ritchie Town of Swansboro Additionally, other subject matter experts, as required, were invited to the planning meetings on an as required basis to include representatives from the Onslow County Tax Office, Onslow County Flood Plain Management Office, American Red Cross – Onslow County Chapter, Marine Corps Base Camp Lejeune Joint Land Use Study Office, and the North Carolina Emergency Management Hazard Mitigation Section.
These representatives, as well as those members of the public who participated, were involved in various aspects of the planning process, advising for the planning process, and in providing background information and analysis.
Onslow County, the surrounding municipalities, and local military installations have formed the Military Civilian Task Force for Emergency Response (MCTFER) group, comprised of emergency management, response, recovery, and support organizations throughout the County. The MCTFER’s mission is to improve public safety by coordinating all regional emergency services resources, both military and civilian, in the event of a regional disaster. The MCTFER brings local and Federal military emergency services personnel under an approved and accepted Incident Command System, providing for a unified response to major incidents that impact our community.
The MCTFER’s organizational responsibilities are to fulfill its military-civilian mutual-aid charter responsibilities in responding to an emergency situation through coordination of all regional emergency services resources, both military and civilian.
Announcements were made at the monthly Onslow County Military Civilian Task Force for Emergency Response (MCTFER) meetings regarding both the formation of the OC Hazard Mitigation Plan Advisory Committee and soliciting both active participation and input to the committee’s efforts.
2.4.1. Multi-Jurisdictional Participation
The Onslow County Multi-Jurisdictional Plan includes one county and five incorporated municipalities. The ensure the multi-jurisdiction plan meets participant requirements, Onslow County and each participating jurisdiction were required to perform the following tasks:
Designate appropriate official(s) to serve on the HMP Advisory Committee 44 CFR Requirements 44 CFR Part 201.6(a)(3): Multi- Participate in mitigation planning meetings and workshops jurisdictional plans may be Provide best available data as required for the risk assessment accepted as long as each jurisdiction has participated in Complete the jurisdictional annex update utilizing the FEMA Review the planning process Tool Identify new and completed mitigation projects and priorities
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Approve and adopt the plan at a jurisdictional level
2.5.Community Involvement and Input
Preparation of the plan required a series of meetings for the Advisory Team to facilitate discussion, develop update timelines, initiate data collection and provided for group input and consensus. Meetings were also held to allow for public input and involvement in the plan update process and to serve as an opportunity to ediucate about hazard mitigation. Below is a summary of key meetings and community workshops that were held in support of the 2015 Onslow County Multi-Jurisdictional Hazrad Mitigation Plan.
Kickoff- February13, 2014
The meeting served as the first meeting for the Hazard Mitigation Advsiory Committee that included participants from the County and all five Municipalities. The primary purpose of the kickoff meeting was to review the FEMA Local Mitigation Plan Review Guide and Toolkit, discuss the current plan, and develop calendar to include meeting schedules, plan deadlines, and develop an update timeline.
Midterm Advisory Meeting – May 29, 2014
The meeting served as an opportunity for the group to discuss specific mitigation concerns, hazard history review and collection, data and statistic resources issues, and questions developing from the FEMA Plan Review Guide and Toolkit.
Final Advisory Meeting – August 14, 2014
The meeting served as a final opportunity for the group to jointly discuss issues, concerns and progress. The group also began discussion on new meeting schedules to begin the following year.
While there were only three in person meetings of the group email chains served to share all information and updates.
2.5.1. Public Workshops ELEMENT A3 44 CFR Part 201.6(b)(1): The A fundamental component of community based hazard mitigation planning Planning process shall involves public participation. Individual participation provides insight into include an opportunity for local concerns and ensures a higher degree of mitigation success by the public to comment on developing community “buy-in”. The public should be engaged to help the plan during the drafting identify community assets and problem areas, describe areas of concern, help stage and prior to plan develop hazard and threat history, help prioritize mitigation priorities and approval. provide ideas for continuing public involvement.
1st Public Hearing(s)
The Onslow County MJ-HMP Advisory Committee made the decision to split the two meeting requirement up into a jurisdictional set of meetings followed by a county level meeting. The initial meetings would be held in the form of public hearings in each of the specific jurisdictions and County council meetings during the approval phase and would address each jurisdictional annex and the County level plan as a whole. Notifications were posted on the County webpage announcing the update process.
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2nd Public Hearing
On September 05, 2014, Onslow County held a public meeting at the Onslow County Emergency Operations Center. This was the last opportunity for the public to provide input and comments before the plan was presented to the Board of Commissioners for tentative approval and adoption contingent upon NCEM and FEMA approval. The public meeting was announced in the Jacksonville Daily News, on the Onslow County website and social media platforms, and distributed to all of the various news and media agencies in the county. The announcement also included the address and phone number of Emergency Service personnel available to answer questions. All citizens of the county, neighboring communities, government agencies, businesses and other interested parties were invited to attend. At the meeting copies of the county document, and several jurisdictional documents were available for viewing. Emergency Services personnel were on hand to answer questions as they arose. Representatives from a local news organization and several citizens attended.
Final Public Hearings
Held once the plan was approved by FEMA and was presented to the County for adoption at a regularly scheduled County Commissioners meeting. Citizens were notified through standard public notices which were posted on the County website and through standard medie notifications. A small follow up presentation was given to reintroduce the plan to the Commissioners and the citizens and to discuss the FEMA approval status. The meeting allowed for a final opportunity for citizen input and comments. Any suggestions for revisions would be carried into the next annual review ELEMENT A244 CFR Part of the plan. 201.6(b)(2): The Planning process shall include an opportunity for 2.5.2. Involving Stakeholders neighboring communities, local and regional agencies involved in In addition to the HMP Advisory Committee meetings, Onslow County and hazard mitigation activities, and participating jurisdictions encourages stakeholder participation in the agencies that have authority to development and update of the plan. Invitational emails were sent to non- regulate development, as well as governmental agencies including public utilities and community outreach business, academia and other groups. As discussed earlier, announcements and invitations were also sent non-profit interests to be involved in the planning process. through the MCTFER group for participation. Stakeholder involvement helps to promote education about the hazards and risks in the local area, develop local impact histories, provide data and information that will improve the overall quality and accuracy of the plan and helps to ensure transparency and build trust.
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3. COMMUNITY PROFILE
This Section provides a general overview of Onslow County. It consists of the following sections:
3.1 Geography and Environment 3.2 Population and Demographics 3.3 Housing, Infrastructure, and Land Use 3.4 Employment and Industry 3.5 Disaster Declarations
3.1.Geography and Environment
North Carolina is subject to many different types of natural hazards including earthquakes, landslides, hurricanes, nor'easters, tornadoes, severe winter weather, wildfires, sinkholes, and flooding. The susceptibility of an area to these events depends largely upon its geographic location.
The climate of North Carolina varies considerably from the mountainous region in the west to the eastern coastline. Average temperatures vary by as much as 20 degrees from west to east. Average annual precipitation is generally around 50 inches statewide, but in the mountains there are significant terrain- induced variations. In light of the west-to-east gradient in climate variability due to topography (and proximity to the Atlantic Ocean) coupled with the north-to-south gradient in temperature due to latitude, North Carolina has been divided into eight climate divisions for purposes of long-term climate assessments. These climate divisions are considered relatively homogeneous in their long-term climatology and generalizations relating to the probability of various hazard events occurring in each climate division can be made.
Onslow County is located in climate division 6 (see the below table - Natural Hazard Vulnerabilities for Counties within Climate Division 6) Based on the characteristics of each climate division, the National Climatic Data Center categorized North Carolina's counties into one of three levels of vulnerability for natural disasters (Low, Moderate, and High). Most of the categorizations were made using the particular county's Climate Division number, which was formulated by the National Climatic Data Center.
Onslow County (OC) is in the North Carolina Emergency Management (NCEM) Eastern Branch (EB), and Federal Emergency Management Agency (FEMA) Region IV. It is geographically located in SE North Carolina approximately 100 miles SE of Raleigh, and 30 miles N of Wilmington. It is bordered on the E by the Atlantic Ocean and Carteret County; on the S by the Atlantic Ocean and Pender County; on the W by Pender and Duplin Counties; and on the N by Jones.
Onslow County consists of flat, gently rolling terrain, which slopes easterly from an altitude of 63 feet above sea level in the town of Richlands to sea level. The average elevation is 23 feet. The County includes 27 miles of unspoiled coastline and a total land area of approximately 819 square miles or approximately 524,000 acres. Of this total, 157,000 acres make up Marine Corps Installations in the County.
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3.2.Population and Demographics
The population of the County and the municipalities within the County is 185,220 (US Census 2013 estimates). Onslow County is the 11th most populated County in NC and is currently ranked as the fastest growing county (NC Office of State Budget and Management 2013). Onslow County sees a moderate increase in population during tourist season and according to the Onslow County Tourism board the estimated peak seasonal population is around 200,000+. There are five incorporated municipalities in Onslow County. The City of Jacksonville is home to the County Seat and is the largest of the municipalities. The areas surrounding the City comprise the major population centers and growth area in the County.
Table 3.1: Onslow County Populations Estimates for 2000 and 2010 Census Jurisdiction 2000 Census 2010 Census Increase % Growth Onslow County 150,355 177,772 27,417 18 Holly Ridge 831 1,268 437 52 Jacksonville 66,715 70,145 3,430 5 North Topsail Beach 843 743 -100 -11 Richlands 928 1,520 592 63 Swansboro 1,426 2,663 1,237 86 Source: US Census 2010
According to the 2010 US Census the median age for Onslow County is 25.8 which is much younger than the North Carolina median age of 37.4. Nearly 18% of the population ranges between 20-24 years old and 9.4% of the population is over the age of 62.
Almost 53% of the population is identified as male and 46% are female. 74% of the population identifies as Caucasian while the next largest group at 15.6% identify as Black or African American. Table 3.1 displays the 2010 US Census data on Onslow County Demographics.
Table 3.2: Race Percentages in Onslow County, 2010 Census Race Population Percent White 138,114 77.7 Black 31,426 17.7 American Indian or Alaskan Native 2,897 1.6 Asian 5,757 3.2 Native Hawaiian/Other Pacific Islander 1,031 0.6 Some Other Race 7,089 4.0 Hispanic or Latino 17,896 10.1 Source: US Census 2010
3.3.Housing, Infrastructure, and Land Use
In the 2010 census there were 68,226 total housing units listed in Onslow County, this is a 23% increase from the 200 census. Of the listed housing units 60,092 were listed as occupied with 34,332 (57.1%) being owner occupied and 25,760 (42.9%) being renter occupied. The average household size in Onslow County is 2.0 persons per household (33.9%). The median home value in Onslow County is $149,900.
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Transportations networks are vital for Onslow County, not only for local transportation but also in support of tourism and 3 military installations. Onslow County is connected through the major thoroughfares of US Highway 17, NC Highway 24, US Highway 258, NC Highway 50 and NC Highway 210. There are 2 bypasses in Jacksonville serving US Highway 17 and NC Highway 24. There thoroughfares also serve as primary evacuation routes. Onslow County is serviced by one civilian airport, Albert J. Ellis, with carriers to include Delta and US Airways. There are currently two transit services operating in Onslow County; Onslow United Transit Services provides commuter bus service throughout areas of the County and Jacksonville Transit Service offers commuter bus services within the City of Jacksonville.
Onslow County has a person per square mile density of 233.1 which is significantly higher than the North Carolina Average of 196.1 persons per square mile. Development, economic growth and expansion of military installations have resulted in an 18.2% population increase since the 2000 census and NC Data Center projects that Onslow County will see a 43.1% increase in population by the year 2034.
Table 3.3: Projected Population Growth for Onslow County, 2010-2034 Jul 2010 July 2015 July 2020 July 2025 July 2030 July 2034 177,772 200,913 217,809 234,706 251,602 265,120 Source: NC OSBM, 2014
Utilities in Onslow County are provided by a mixture of government and non-government corporations. Currently water and wastewater are provided by two primary providers; Onslow Water and Sewer Authority (ONWASA) and City of Jacksonville Public Services Department. MCB Camp Lejeune also maintains a water/wastewater system that supports the military installation. Power utilities are provided primarily by Duke (Progress) Energy and Jones Onslow Electric Membership Cooperative with 2 out of county providers covering small portions near the County lines. Currently North Carolina Natural Gas, a subsidiary of Piedmont Natural Gas, provides natural gas into Onslow County.
According to the Onslow County 2009 CAMA Plan approximately 57.6% of land in the county is listed as unincorporated, 16.4% is listed as incorporated, and 26.0% is listed as military installation. Roughly 38% of the unincorporated areas of the county are listed as vacant and 40% are listed as non-county jurisdiction (forest lands, State property and military installations). Approximately 18.9% of unincorporated lands are listed as residential use, .19% as Office/Institutional, .22% Commercial and 1.4% as Industrial. Future land use in the CAMA Plan revolves around meeting the demands for each identified use based on the projected population growth.
3.4.Employment and Industry
The median household income for Onslow County is listed as $45,812 in the 2010 US Census (North Carolina median income is $46,450). The average state unemployment rate in 2013 was 6.2% while the average for Onslow County was approximately 6.7%. Approximately 11.1% of the citizens in Onslow County are listed as falling below the national poverty level which is slightly below the North Carolina level of 12.4%.
Onslow County promotes a diversified economy with approximately 66.1% of employment being concentrated in the private sector. As a community with 3 military installations however, government workers make up almost 27.5% of the workforce. This is higher than the North Carolina average of 15.3%. The following table provides an overview of the economic sectors n Onslow County.
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Table 3.4: Employment by Sector for Onslow County, 2010 Census Employment Sector Workforce Percentage Agriculture, forestry, fishing and hunting, and mining 791 1.4% Construction 5,566 9.6% Manufacturing 1,553 2.7% Wholesale trade 1,097 1.9% Retail trade 7,118 12.3% Transportation and warehousing, and utilities 2,693 4.7% Information 898 1.6% Finance and insurance, and real estate and rental and leasing 2,548 4.4% Professional/scientific/management/ administrative and waste management 4,874 8.4% Educational services, and health care and social assistance 11,658 20.2% Arts/entertainment/recreation/accommodation and food services 8,320 14.4% Other services, except public administration 3,033 5.2% Public administration 7,623 13.2% Source: US Census 2010
3.5.Disaster Declarations
Since 1965 Onslow County has experienced 11 presidential disaster declarations as shown in Table 3.5. There have been many other emergencies and disasters that did not qualify for federal disaster relief.
Table 3.5: Presidential Disaster Declarations Event Declaration Date Declaration Number Hurricane Diana 09/21/1984 DR-724 Hurricane Bertha 07/18/1996 DR-1127 Hurricane Fran 09/10/1996 DR-1134 Hurricane Bonnie 08/27/1998 DR-1240 Hurricane Floyd 09/21/1999 DR-1292 Hurricane Isabel 09/18/2003 DR-1490 Hurricane Ophelia 10/7/2005 DR- 1608 Tropical Storm Hanna 10/8/2008 DR-1801 Severe Storms/Tornadoes 04/19/2011 DR1969 Tropical Storm Nicole 10/14/2011 DR1942 Hurricane Irene 08/31/2011 DR4019 Source: Federal Emergency Management Agency
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4. HAZARD IDENTIFICATION AND ANALYSIS
Onslow County is vulnerable to a wide range of natural hazards that have a potential to threaten life and property. This section of the plan describes the hazards that have been identified as posing a threat to the people and property located within the county and its five jurisdictions. Each hazard is described with an assessment to include background information, location/spatial extent, historical occurrences and probability of future occurrences. The hazards addressed in this plan were identified through research, past disaster declarations, previous hazard identification plans, and by comparing against the current North Carolina Hazard Mitigation Plan. All information used to develop the assessment of each hazard is available online through various agencies including federal, state and academic sites and through library research tools.
The following natural hazards were identified:
Atmospheric o 4.2 Drought and Heat Wave o 4.3 Severe Thunderstorm and Hail ELEMENTS B1 & B244 CFR Part 201.6(c)(2)(i): o 4.4 Hurricane and Coastal Storm (includes Nor’easter) B1: The Risk assessment shall o 4.5 Tornado include a description of the o 4.6 Winter Storm type, location, and extent of all natural hazards that can Geologic affect the jurisdiction.
o 4.7 Earthquake B2: The plan shall include o 4.8 Landslide and Sinkhole information on previous o 4.9 Tsunami occurrences of hazard events and on the probability of Hydrologic future hazard events.
o 4.10 Coastal and Riverrine Erosion o 4.11 Dam and Levee Failure o 4.12 Flooding o 4.13 Storm Surge
Other o Wildfire
Some hazards are considered to be interrelated and cascading (i.e. hurricanes can cause flooding, storm surge and tornadoes), but for hazard identification purposes each hazard is treated as a unique and stand alone hazard. It should also be noted that some hazards, such as earthquakes and winter storms, may impact large areas yet cause little damage, while other hazards, such as tornado, may impact a smaller geographic area but cause substantially more damage.
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4.1.Study Area
The study area pertains to all of the unincorporated areas of Onslow County and the municipalities of Holly Ridge, Jacksonville, North Topsail Beach, Richlands, and Swansboro and their relative extraterritorial jurisdictions (ETJ’s). While the non-participating areas of Camp Lejeune and their coordinating installations of Camp Johnson, Camp Geiger, Stone Bay Range and MCAS New River are not analyzed specifically the hazard identification and analysis will pertain to the extent that the same hazards will affect those areas. Onslow County and Camp Lejeune work closely together on various planning and response activities and share many of our plans with one another. Camp Lejeune will house a copy of the OC MJ_HMP as Onslow County houses a copy of the Camp Lejeune HMP.
Figure 4.1: Onslow County Study Area
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ATMOSPHERIC HAZARDS
4.2.Drought and Heat Wave
4.2.1. Background
Drought refers to a deficiency in precipitation over an extended period, usually a season or more, resulting in water shortages that can cause adverse impacts on vegetation, animals, and/or people. Drought is a normal and recurrent feature of climate that occurs in virtually all climate zones and usually presents as an aberration from normal climatic conditions. Human factors, including water demands and water management, can exacerbate the impacts of a drought on a region. Drought is classified as: 1) meteorological, 2) hydrological and 3) agricultural.
Table 4.1: Drought Classifications Usually defined based on the degree of dryness (in comparison to some Meteorological “normal” or average) and the duration of the dry period. Drought onset generally occurs with a meteorological drought. Usually occurs following periods of extended precipitation shortfalls that Hydrological impact water supply (i.e. streamflow, reservoir and lake levels, ground water), potentially resulting in significant societal impacts. Links various characteristics of meteorological (or hydrological) drought to agricultural impacts, focusing on precipation shortages, soil water Agricultural deficits, reduced ground water or reservoir levels needed for irrigation, and so forth. Source: National Weather Service’s: NOAA
Drought events are typically slow onset hazards but can, over time, have very widespread damaging affects to crops, public water supplies and recreational activities. Long term, persistant droughts can incidentally increase an areas risk to wildfire.
Drought is currently monitored by the National Integrated Drought Information Systems, a collaborative effort lead by the National Oceanic and Atmospheric Administration (NOAA) and partners including USDA, USGS, US Army Corps of Engineers, and several academic agencies. The NIDIS provides daily drought monitoring reports along with seasonal drought outlooks products. Drought forecast products are produced in 6 month increments showing the potential for development and persistence of drought conditions.
The Palmer Drought Severity Index (PDSI) is a measure of drought that is widely used in the United States for tracking moisture conditions. The PDSI is defined as “an interval of time, generally in months or years in duration, during which the actual moisture supply at a given place rather consistently falls short of the climatically expected or climatically appropriate moisture supply.” The range of PDSI is from –4.0 (extremely dry) to +4.0 (excessively wet), with the central half (–2.0 to +2.0) representing the normal or near normal conditions. The PDSI is best used for long-term measurements of drought. For short-term (week-to-week) measurements, it is more useful to use the Crop Moisture Index (CMI), also developed by Wayne Palmer.
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Figure 4.2: Drought Outlook Product
While drought and heat wave often coincide the two natural occurrences are not always directly related. The National Weather Service does not offer a direct definition of a heat wave but it is generally accepted as describing a period of three or more days where temperatures reach (90) degrees Fahrenheit or higher. It can however, be described as any event lasting three or more days where temperatures are 10 degrees hotter than the normal temperatures. Heat waves can pose serious threats to life. The National Weather Service began issuing products to help with heat warnings for the general public. Table 4.2 lists each product with a definition.
Table 4.2: NWS Heat Warning Products Issued when the potential exists for an excessive heat event in the next 3-7 days. An Outlook provides information to those who need considerable lead time to Excessive Heat Outlooks prepare for the event, such as public utility staff, emergency managers and public health officials. See the mean heat index and probability forecasts maps Issued when conditions are favorable for an excessive heat event in the next 24 to 72 hours. A Watch is used when the risk of a heat wave has increased but its Excessive Heat Watches occurrence and timing is still uncertain. A Watch provides enough lead time so that those who need to prepare can do so, such as cities officials who have excessive heat event mitigation plans. Issued when an excessive heat event is expected in the next 36 hours. These products are issued when an excessive heat event is occurring, is imminent, or has a very high probability of occurring. The warning is used for conditions posing a Excessive Heat Warning/Advisories threat to life. An advisory is for less serious conditions that cause significant discomfort or inconvenience and, if caution is not taken, could lead to a threat to life. Source: National Weather Service
As a part of producing watches and warnings the NWS developed a Heat Index as a mechanism to help better inform the public of the dangers of heart. The Heat Index Chart, listed in Figure 4.3, uses a combination of air temperature and humidity to help determine the heat index (or apparent temperature). Populations such as the elderly and young are more susceptible to heat dangers than other segments of the population.
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Figure 4.3: NWS Heat Index
Table 4.3: Heat Index and Heat Disorder Heat Index Possible heat disorders for people in higher risk groups 80° - 90° Fatigue possible with prolonged exposure and/or physical activity. 90°- 105° Sunstroke, heat cramps and exhaustion possible with prolonged exposure and/or physical activity. 105°- 130° Sunstroke, heat cramps or heat exhaustion likely, and heatstroke possible with prolonged exposure and/or physical activity. 130° or higher Heatstroke/sunstroke highly likely with continued exposure. Source: National Weather Service
During periods of extreme heat, people generally restrict their outdoor activities. However, by retiring indoors there is then an increased demand for air conditioning creating increased electrical demands. Depending on the electrical demand and generation capacity, there is potential for placing stress on the electric grid, which can potentially fail. While this has not been a significant problem for Onslow County residents, other regions of the country, especially the Northeast, have suffered the results of widespread electrical failure and outages significantly impacting daily life and commerce.
Agriculture concerns, such as poultry and swine operations are most susceptible to extreme heat. Extreme heat can and does cause extensive poultry deaths. Livestock, while susceptible to extreme heat can be cared for easier than poultry.
4.2.2. Location and Spatial Extent
Drought typically covers large areas and cannot be confined to geographical or political boundaries. While North Carolina has a relatively low risk for drought hazard local areas may experience more severe and/or frequent drought conditions than other areas. It is assumed that all of Onslow County would experience drought uniformly within its boundaries.
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Similar to drought, heat wave can occur anywhere in the U.S. and has no true geographical or political boundaries. It is also assumed that all of Onslow County would experience drought and heat wave uniformly within its boundaries however, coastal areas may have a slightly reduced risk due to ocean winds.
4.2.3. Historical Occurrences
The North Carolina Drought Management Advisory Council reports data on North Carolina drought conditions from January 2000 to June 2009. It classifies counties on a scale of D0 to D4:
CLASSIFICATION INTENSITY PHRASE YEAR DECLARED 2000 2001 2002 2004 2005 2006 2007 DO ABNORMALLY DRY 2008 2009 2010 2011 2012 2013 2014 2001 2002 2007 2008 D1 MODERATE DROUGHT 2009 2010 2011 2012 2001 2002 D2 SEVERE DROUGHT 2008 2011 2007 D3 EXTREME DROUGHT 2008 2011 D4 EXCEPTIONAL DROUGHT SOURCE: North Carolina Drought Monitor
Data from the National Climate Data Center and North Carolina Drought Management Advisory Council were utilized to develop a historical occurrence of Drought. According to these records Onslow County experienced 3 periods documented as extreme drought:
July 2011-August 2011 November 2007-Februsary 2008 September 2007-October 2007
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From 1994 thru 2008, the area experienced a rainfall reduction, resulting in near drought and moderate drought conditions. Drought conditions present a danger that is becoming more evident over time. Onslow County pulls water from aquifers and deep water wells and has felt minimal impact in the recent droughts.
In recent years, Onslow County has had no reported extreme heat fatalities due to extreme heat. Onslow Memorial Hospital reports that from 2000 through 2008, 234 outpatients, and 16 in-patients were treated due to the effects of extreme heat. However, statewide there were ten (10) fatalities reported in 2002 and seven (7) in 2003. From 1930 to 1996, normal daily maximum temperatures did not exceed 88.9 degrees (F) with a mean daily maximum of 89.1 degrees (F). However, temperatures have reached 103 degrees (F) and above in 1954, 1983 and 1986, with a maximum high of 104 degrees (F) in September of 1954.
4.2.4. Probability of Future Occurrences
Given uniform exposure, climatic changes and the history of previous drought events it is assumed that there is a likely probability of future drought and heat wave occurances in Onslow County.
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4.3.Severe Thunderstorm and Hail
4.3.1. Background
Thunderstorms are the result of convection in the atmosphere. They are typically the by-product of atmospheric instability, where air masses of varying temperatures meet. Rapidly rising warm moist air serves as the engine for thunderstorms. .
A typical thunderstorm may be three miles wide at its base, rise to between 40,000 to 60,000 feet in the troposphere, and contain half a million tons of condensed water. Conglomerations of thunderstorms along cold fronts (with squall lines) can extend for hundreds of miles.
Thunderstorms contain tremendous amounts of energy derived from water condensation. According to the National Weather Service, thunder storm is classified as severe when it produces one of three elements: 1) a tornado, 2) hail at least 0.75 inches in diameter, or 3) winds at least 58 miles per hour.
While thunderstorms can occur in all regions of the United States, they are most common in the central and southern states because atmospheric conditions in these regions are most favorable for generating powerful storms. Figure 4.4 illustrates thunderstorm hazard severity based on the annual average number of thunder events.
Figure 4.4: Annual Average Severe Thunderstorm
Source: NOAA: Storm Prediction Center
Hailstorms are a potentially damaging formation of severe thunderstorms. Hail is created when strong rising currents of air within the storm, called updrafts, carry water droplets to a height where they freeze. Ice particle will continue to grow in size, eventually (larger than .75 inches) becoming too heavy to be supported by the updraft, and fall to the ground. Hail is larger than sleet and will only form inside a thunderstorm. The size of the hailstones are a direct function of the size
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 8 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 and severity of the storm.
4.3.2. Location and Spatial Extent
Thunderstorms are common throughout the State and have occurred in all months. Thunderstorm-related deaths and injuries in North Carolina (1959-1992) have peaked during July and August.
Hail events may occur anywhere throughout Onslow County and will not be confined by geographic boundaries. Hail events typically are widespread.
4.3.3. Historical Occurrences
According to the National Climatic Data Center there were 101 thunderstorm events in Onslow County between January 1, 1950 and April 30, 2014. These events resulted in over $157 thousand in property damage (2014 estimates). Table 4.4 lists historical occurrences of thunderstorm events in Onslow County.
Table 4.4: Thunderstorm Occurrences in Onslow County Property Date of Death/
Location Type Magnitude Damage Occurrence Injury (2014 Dollars) Onslow County 05/28/1965 Thunderstorm Wind 51 kts. 0/0 0.00K Onslow County 07/04/1979 Thunderstorm Wind 55 kts. 0/0 0.00K Onslow County 12/24/1979 Thunderstorm Wind 63 kts. 0/0 0.00K Onslow County 07/10/1980 Thunderstorm Wind 55 kts. 0/0 0.00K Onslow County 06/05/1982 Thunderstorm Wind 50 kts. 0/0 0.00K Onslow County 06/16/1982 Thunderstorm Wind 54 kts. 0/0 0.00K Onslow County 03/21/1983 Thunderstorm Wind 78 kts. 0/0 0.00K Onslow County 09/12/1983 Thunderstorm Wind 61 kts. 0/0 0.00K Onslow County 05/08/1984 Thunderstorm Wind 50 kts. 0/0 0.00K Onslow County 07/17/1984 Thunderstorm Wind 55 kts. 0/0 0.00K Onslow County 09/15/1984 Thunderstorm Wind 50 kts. 0/0 0.00K Onslow County 07/27/1986 Thunderstorm Wind 65 kts. 0/0 0.00K Onslow County 06/03/1987 Thunderstorm Wind 50 kts. 0/0 0.00K Onslow County 07/13/1988 Thunderstorm Wind 54 kts. 0/0 0.00K
Sneads Ferry 06/12/1995 Thunderstorm Wind 60 kts. 0/0 5.00K
Swansboro 10/28/1995 Thunderstorm Wind 74 kts. 0/0 0.00K
SWANSBORO 10/08/1996 Thunderstorm Wind 51 kts. 0/0 0.00K
SNEADS FERRY 02/15/1997 Thunderstorm Wind 51 kts. 0/0 0.00K
HUBERT 06/03/1997 Thunderstorm Wind 50 kts. 0/0 0.00K
PINEY GREEN 06/14/1997 Thunderstorm Wind 50 kts. 0/0 0.00K
SWANSBORO 08/18/1997 Thunderstorm Wind 50 kts. 0/0 0.00K
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JACKSONVILLE 09/15/1997 Thunderstorm Wind 52 kts. 0/0 15.00K
RICHLANDS 05/23/1998 Thunderstorm Wind 59 kts. 0/0 0.00K
HUBERT 06/13/1998 Thunderstorm Wind 50 kts. 0/0 0.00K
RICHLANDS 06/23/1998 Thunderstorm Wind 61 kts. 0/0 0.00K
HOLLY RIDGE 06/23/1998 Thunderstorm Wind 50 kts. 0/0 0.00K
CAMP LEJEUNE 06/23/1998 Thunderstorm Wind 51 kts. 0/0 0.00K
NORTH TOPSAIL BEACH 06/23/1998 Thunderstorm Wind 50 kts. 0/0 0.00K
JACKSONVILLE 06/30/1998 Thunderstorm Wind 50 kts. 0/0 0.00K
JACKSONVILLE 08/29/1998 Thunderstorm Wind 51 kts. 0/0 0.00K
HAW 03/03/1999 Thunderstorm Wind 55 kts. 0/0 0.00K
JACKSONVILLE 06/10/1999 Thunderstorm Wind 50 kts. 0/0 0.00K
JACKSONVILLE 07/24/1999 Thunderstorm Wind 50 kts. 0/0 0.00K
(NCA)MCAS NEW RIVER 11/02/1999 Thunderstorm Wind 52 kts. 0/0 0.00K
RICHLANDS 06/22/2000 Thunderstorm Wind 55 kts. E 0/0 0.00K
CATHERINE LAKE 04/01/2001 Thunderstorm Wind 56 kts. E 0/0 5.00K
HUBERT 04/01/2001 Thunderstorm Wind 61 kts. E 0/0 0.00K
SWANSBORO 08/28/2001 Thunderstorm Wind 52 kts. M 0/0 0.00K
HALF MOON 06/14/2002 Thunderstorm Wind 61 kts. E 0/0 10.00K
SNEADS FERRY 07/05/2002 Thunderstorm Wind 52 kts. M 0/0 0.00K
CAMP LEJEUNE 07/10/2002 Thunderstorm Wind 62 kts. E 0/0 20.00K
PINEY GREEN 07/10/2002 Thunderstorm Wind 62 kts. E 0/0 1.00K
BELGRADE 07/20/2002 Thunderstorm Wind 52 kts. E 0/0 0.00K
CAMP LEJEUNE 07/31/2002 Thunderstorm Wind 56 kts. M 0/0 0.00K
JACKSONVILLE 08/20/2002 Thunderstorm Wind 52 kts. E 0/0 0.00K
North Topsail Beach 11/12/2002 Thunderstorm Wind 52 kts. M 0/0 0.00K
SWANSBORO 11/12/2002 Thunderstorm Wind 54 kts. M 0/0 0.00K
JACKSONVILLE 02/22/2003 Thunderstorm Wind 50 kts. EG 0/0 0.00K
JACKSONVILLE 07/17/2003 Thunderstorm Wind 50 kts. EG 0/0 0.00K
HUBERT 07/09/2004 Thunderstorm Wind 50 kts. EG 0/0 1.00K
JACKSONVILLE 07/11/2004 Thunderstorm Wind 50 kts. EG 0/0 0.00K
RICHLANDS 03/08/2005 Thunderstorm Wind 50 kts. EG 0/0 25.00K
SWANSBORO 03/08/2005 Thunderstorm Wind 53 kts. MG 0/0 10.00K
JACKSONVILLE 07/28/2005 Thunderstorm Wind 50 kts. EG 0/0 0.00K
CAMP LEJEUNE 08/23/2005 Thunderstorm Wind 51 kts. EG 0/0 0.00K
CAMP LEJEUNE 04/17/2006 Thunderstorm Wind 52 kts. MG 0/0 0.00K
JACKSONVILLE 05/26/2006 Thunderstorm Wind 50 kts. EG 0/0 0.00K
RICHLANDS 05/26/2006 Thunderstorm Wind 60 kts. EG 0/0 50.00K
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SWANSBORO 06/03/2006 Thunderstorm Wind 50 kts. EG 0/0 0.00K
HUBERT 07/15/2006 Thunderstorm Wind 51 kts. EG 0/0 0.00K
HALF MOON 07/23/2006 Thunderstorm Wind 51 kts. EG 0/0 0.00K
GREGORY FORKS 03/04/2008 Thunderstorm Wind 50 kts. EG 0/0 0.00K
HUBERT 03/05/2008 Thunderstorm Wind 50 kts. EG 0/0 0.00K
SHELL ROCK LNDG 03/05/2008 Thunderstorm Wind 68 kts. MG 0/0 0.00K
ERVINTOWN 04/12/2008 Thunderstorm Wind 50 kts. EG 0/0 0.00K
BELL FORK 06/01/2008 Thunderstorm Wind 52 kts. EG 0/0 0.00K
CATHERINE LAKE 06/29/2008 Thunderstorm Wind 50 kts. EG 0/0 0.00K
CAMP LEJEUNE JCT 06/29/2008 Thunderstorm Wind 52 kts. EG 0/0 0.00K
FRANKTOWN 06/29/2008 Thunderstorm Wind 60 kts. EG 0/0 5.00K
MORTON FORK 06/13/2009 Thunderstorm Wind 50 kts. EG 0/0 0.00K
HOLLY RIDGE 06/26/2009 Thunderstorm Wind 50 kts. EG 0/0 0.00K
KELLUM 07/17/2009 Thunderstorm Wind 50 kts. EG 0/0 0.00K
ERVINTOWN 08/11/2009 Thunderstorm Wind 50 kts. EG 0/0 0.00K
GREGORY FORKS 05/16/2010 Thunderstorm Wind 50 kts. EG 0/0 0.00K
ERVINTOWN 05/16/2010 Thunderstorm Wind 50 kts. EG 0/0 0.00K
MIDWAY PARK 06/13/2010 Thunderstorm Wind 50 kts. EG 0/0 0.00K
ERVINTOWN 06/16/2010 Thunderstorm Wind 63 kts. MG 0/0 0.00K
HALF MOON 06/29/2010 Thunderstorm Wind 50 kts. EG 0/0 0.00K
GREGORY FORKS 06/29/2010 Thunderstorm Wind 50 kts. EG 0/0 0.00K
NORTH TOPSAIL BEACH 07/18/2010 Thunderstorm Wind 50 kts. EG 0/0 0.00K
RICHLANDS 04/05/2011 Thunderstorm Wind 50 kts. EG 0/0 0.40K
GREGORY FORKS 04/05/2011 Thunderstorm Wind 50 kts. EG 0/0 0.00K
ONSLOW CO. 06/17/2011 Thunderstorm Wind 50 kts. EG 0/0 0.00K
ONSLOW CO. 06/23/2011 Thunderstorm Wind 50 kts. EG 0/0 0.00K
JCKSNVLL ELLIS ARPT 07/23/2011 Thunderstorm Wind 50 kts. EG 0/0 0.00K
(NCA)MCAS NEW RIVER 07/24/2011 Thunderstorm Wind 59 kts. MG 0/0 0.00K
PUMPKIN CENTER 07/24/2011 Thunderstorm Wind 50 kts. EG 0/0 0.00K
KELLUM 07/24/2011 Thunderstorm Wind 50 kts. EG 0/0 0.00K
BELL FORK 07/24/2011 Thunderstorm Wind 50 kts. EG 0/0 0.00K
KELLUMTOWN 07/24/2011 Thunderstorm Wind 50 kts. EG 0/0 0.00K
GUM BRANCH 05/22/2012 Thunderstorm Wind 50 kts. EG 0/0 0.00K
ERVINTOWN 07/01/2012 Thunderstorm Wind 50 kts. EG 0/0 0.00K
(OAJ)ELLIS FLD JACKS 07/01/2012 Thunderstorm Wind 50 kts. EG 0/0 0.00K
HAWKSIDE 07/01/2012 Thunderstorm Wind 50 kts. EG 0/0 0.00K
(NCA)MCAS NEW RIVER 07/01/2012 Thunderstorm Wind 54 kts. MG 0/0 0.00K
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BELL FORK 07/24/2012 Thunderstorm Wind 50 kts. EG 0/0 0.00K
TAR LNDG 01/31/2013 Thunderstorm Wind 50 kts. EG 0/0 0.00K
WILLIS LNDG 11/26/2013 Thunderstorm Wind 55 kts. EG 0/0 10.00K
JARMANTOWN 02/21/2014 Thunderstorm Wind 50 kts. EG 0/0 0.00K
BELL FORK 04/30/2014 Thunderstorm Wind 52 kts. EG 0/0 0.50K
BELL FORK 04/30/2014 Thunderstorm Wind 52 kts. EG 0/0 0.00K Totals: 0/0 157.90K
According to the National Climatic Data Center there have been 160 hail events in Onslow County that documented hail of .75 inches in diameter or larger. The largest recorded hailstone in Onslow County is 2.75 inches in diameter. No causalities or damages were reported from these events. Standard sizes for Onslow County are the size of a penny or a nickel. Table 4.5 lists historical occurrences of hail events in Onslow County. Figure 4.5 shows recorded occurrences of hail throughout Onslow County.
Table 4.5: Hail Occurrences in Onslow County
Property Death/
Location Date Type Magnitude Damages Injury (2014 dollars) Totals: 0 0.00K
Onslow County 06/23/1974 Hail 0.75 in. 0 0.00K Onslow County 04/26/1978 Hail 0.75 in. 0 0.00K Onslow County 08/21/1979 Hail 1.75 in. 0 0.00K Onslow County 05/19/1981 Hail 1.75 in. 0 0.00K Onslow County 03/21/1983 Hail 0.75 in. 0 0.00K Onslow County 03/21/1983 Hail 0.75 in. 0 0.00K Onslow County 06/15/1984 Hail 1.75 in. 0 0.00K Onslow County 09/15/1984 Hail 1.75 in. 0 0.00K Onslow County 05/25/1986 Hail 1.75 in. 0 0.00K Onslow County 05/10/1988 Hail 1.75 in. 0 0.00K Onslow County 04/27/1989 Hail 1.75 in. 0 0.00K Onslow County 05/20/1990 Hail 1.00 in. 0 0.00K Onslow County 06/21/1992 Hail 2.50 in. 0 0.00K Onslow County 06/21/1992 Hail 1.75 in. 0 0.00K Richlands 03/24/1993 Hail 0.75 in. 0 0.00K Holly Ridge 05/15/1995 Hail 0.75 in. 0 0.00K SNEADS FERRY 05/06/1996 Hail 0.75 in. 0 0.00K Jacksonville 07/03/1996 Hail 0.75 in. 0 0.00K Jacksonville 07/03/1996 Hail 1.00 in. 0 0.00K
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 12 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
Jacksonville 07/28/1996 Hail 1.50 in. 0 0.00K Richlands 04/21/1997 Hail 1.00 in. 0 0.00K Deppe 04/21/1997 Hail 1.75 in. 0 0.00K Deppe 04/21/1997 Hail 2.75 in. 0 0.00K Richlands 05/13/1997 Hail 0.75 in. 0 0.00K Jacksonville 07/05/1997 Hail 0.75 in. 0 0.00K Catherine Lake 08/05/1997 Hail 1.00 in. 0 0.00K Jacksonville 05/04/1998 Hail 0.75 in. 0 0.00K Jacksonville 05/04/1998 Hail 0.75 in. 0 0.00K Sneads Ferry 05/04/1998 Hail 0.75 in. 0 0.00K Holly Ridge 05/08/1998 Hail 0.75 in. 0 0.00K Bear Creek 05/27/1998 Hail 0.75 in. 0 0.00K Swansboro 05/27/1998 Hail 0.75 in. 0 0.00K Richlands 06/23/1998 Hail 1.00 in. 0 0.00K Jacksonville 06/23/1998 Hail 1.75 in. 0 0.00K Camp Lejeune 06/23/1998 Hail 1.75 in. 0 0.00K Verona 02/28/1999 Hail 0.75 in. 0 0.00K Halfmoon 08/11/1999 Hail 0.88 in. 0 0.00K Sneads Ferry 04/18/2000 Hail 0.75 in. 0 0.00K Richlands 05/28/2000 Hail 0.75 in. 0 0.00K Verona 08/13/2000 Hail 0.75 in. 0 0.00K Swansboro 08/13/2000 Hail 0.75 in. 0 0.00K Haw Branch 04/01/2001 Hail 0.75 in. 0 0.00K (OAJ)ELLIS FLD JACKS 04/01/2001 Hail 0.75 in. 0 0.00K Catherine Lake 04/01/2001 Hail 0.75 in. 0 0.00K Jacksonville 04/01/2001 Hail 1.75 in. 0 0.00K Haw Branch 05/12/2001 Hail 1.25 in. 0 0.00K Richlands 05/20/2001 Hail 0.75 in. 0 0.00K Haw Branch 05/26/2001 Hail 0.75 in. 0 0.00K Jacksonville 05/28/2001 Hail 0.75 in. 0 0.00K Camp Lejeune 07/06/2001 Hail 0.75 in. 0 0.00K Richlands 06/14/2002 Hail 0.88 in. 0 0.00K Haw Branch 07/10/2002 Hail 0.75 in. 0 0.00K Haw Branch 08/19/2002 Hail 1.25 in. 0 0.00K Richlands 03/06/2003 Hail 0.88 in. 0 0.00K Catherine Lake 04/30/2003 Hail 1.00 in. 0 0.00K Belgrade 07/17/2003 Hail 1.00 in. 0 0.00K
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Richlands 06/11/2004 Hail 0.75 in. 0 0.00K Piney Green 07/11/2004 Hail 1.75 in. 0 0.00K Jacksonville 10/13/2004 Hail 0.75 in. 0 0.00K NORTH TOPSAIL BEACH 05/24/2005 Hail 0.88 in. 0 0.00K Camp Lejeune 08/03/2005 Hail 0.75 in. 0 0.00K Camp Lejeune 08/16/2005 Hail 0.75 in. 0 0.00K Jacksonville 04/03/2006 Hail 1.25 in. 0 0.00K (NCA)MCAS NEW RIVER 04/17/2006 Hail 0.75 in. 0 0.00K Swansboro 04/17/2006 Hail 1.00 in. 0 0.00K Jacksonville 05/26/2006 Hail 0.75 in. 0 0.00K Jacksonville 05/26/2006 Hail 1.50 in. 0 0.00K Catherine Lake 06/03/2006 Hail 1.00 in. 0 0.00K Camp Lejeune 06/05/2006 Hail 0.75 in. 0 0.00K Swansboro 06/05/2006 Hail 0.88 in. 0 0.00K Jacksonville 06/06/2006 Hail 0.75 in. 0 0.00K Piney Green 06/06/2006 Hail 0.75 in. 0 0.00K Swansboro 06/06/2006 Hail 1.00 in. 0 0.00K Camp Lejeune 06/06/2006 Hail 1.75 in. 0 0.00K HUBERT 06/06/2006 Hail 0.75 in. 0 0.00K Richlands 06/12/2006 Hail 0.88 in. 0 0.00K Jacksonville 06/28/2006 Hail 1.00 in. 0 0.00K Richlands 06/28/2006 Hail 1.00 in. 0 0.00K Jacksonville 06/30/2006 Hail 0.75 in. 0 0.00K Jacksonville 07/29/2006 Hail 0.75 in. 0 0.00K HUBERT 08/05/2006 Hail 0.75 in. 0 0.00K Haw Branch 06/05/2007 Hail 0.75 in. 0 0.00K (NCA)MCAS NEW RIVER 06/05/2007 Hail 0.88 in. 0 0.00K Bell Fork 06/05/2007 Hail 1.00 in. 0 0.00K Bell Fork 06/05/2007 Hail 0.75 in. 0 0.00K SKY MANOR ARPT 06/05/2007 Hail 1.75 in. 0 0.00K CATHERINE LAKE 06/05/2007 Hail 0.88 in. 0 0.00K ERVINTOWN 06/05/2007 Hail 0.75 in. 0 0.00K MORTON FORK 06/12/2007 Hail 0.75 in. 0 0.00K Belgrade 06/16/2007 Hail 0.75 in. 0 0.00K Swansboro 04/21/2008 Hail 1.00 in. 0 0.00K Swansboro 04/21/2008 Hail 1.50 in. 0 0.00K Swansboro 04/21/2008 Hail 1.00 in. 0 0.00K
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 14 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
SKY MANOR ARPT 04/21/2008 Hail 0.75 in. 0 0.00K ERVINTOWN 04/21/2008 Hail 0.75 in. 0 0.00K Bell Fork 05/05/2008 Hail 0.88 in. 0 0.00K MIDWAY PARK 05/05/2008 Hail 0.88 in. 0 0.00K Bell Fork 05/05/2008 Hail 0.75 in. 0 0.00K KELLUMTOWN 05/05/2008 Hail 0.75 in. 0 0.00K Bell Fork 05/05/2008 Hail 0.75 in. 0 0.00K Bell Fork 05/05/2008 Hail 0.75 in. 0 0.00K Catherine Lake 05/05/2008 Hail 0.75 in. 0 0.00K ERVINTOWN 05/10/2008 Hail 0.75 in. 0 0.00K Bell Fork 05/10/2008 Hail 1.00 in. 0 0.00K Halfmoon 05/10/2008 Hail 0.75 in. 0 0.00K Bell Fork 05/10/2008 Hail 0.75 in. 0 0.00K HUBERT 05/10/2008 Hail 0.75 in. 0 0.00K Haw Branch 05/11/2008 Hail 0.75 in. 0 0.00K Bell Fork 05/11/2008 Hail 0.88 in. 0 0.00K PALO ALTO 05/11/2008 Hail 0.75 in. 0 0.00K Bell Fork 05/11/2008 Hail 0.88 in. 0 0.00K Bell Fork 05/11/2008 Hail 0.75 in. 0 0.00K Bell Fork 05/11/2008 Hail 0.88 in. 0 0.00K MIDWAY PARK 05/11/2008 Hail 0.75 in. 0 0.00K MIDWAY PARK 05/11/2008 Hail 0.88 in. 0 0.00K CATHERINE LAKE 05/20/2008 Hail 0.75 in. 0 0.00K Bell Fork 05/20/2008 Hail 0.75 in. 0 0.00K Verona 05/20/2008 Hail 0.75 in. 0 0.00K Bell Fork 06/01/2008 Hail 0.75 in. 0 0.00K Bell Fork 06/01/2008 Hail 0.75 in. 0 0.00K KELLUMTOWN 06/01/2008 Hail 0.88 in. 0 0.00K MIDWAY PARK 06/01/2008 Hail 1.00 in. 0 0.00K Bell Fork 06/01/2008 Hail 0.75 in. 0 0.00K Bell Fork 06/29/2008 Hail 1.50 in. 0 0.00K Camp Lejeune 06/29/2008 Hail 2.00 in. 0 0.00K Bell Fork 06/29/2008 Hail 0.88 in. 0 0.00K Halfmoon 06/29/2008 Hail 1.00 in. 0 0.00K HUBERT 07/21/2008 Hail 0.88 in. 0 0.00K Belgrade 10/01/2008 Hail 0.75 in. 0 0.00K Belgrade 06/13/2009 Hail 1.75 in. 0 0.00K
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 15 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
Belgrade 06/13/2009 Hail 0.75 in. 0 0.00K Deppe 06/13/2009 Hail 0.75 in. 0 0.00K Catherine Lake 07/23/2009 Hail 0.75 in. 0 0.00K Catherine Lake 07/24/2009 Hail 0.75 in. 0 0.00K GUM BRANCH 07/24/2009 Hail 0.75 in. 0 0.00K Halfmoon 07/24/2009 Hail 0.88 in. 0 0.00K Verona 07/24/2009 Hail 0.88 in. 0 0.00K Halfmoon 07/24/2009 Hail 0.75 in. 0 0.00K MIDWAY PARK 07/24/2009 Hail 0.75 in. 0 0.00K JARMANTOWN 08/05/2009 Hail 0.75 in. 0 0.00K ERVINTOWN 08/05/2009 Hail 0.75 in. 0 0.00K TAR LNDG 10/13/2010 Hail 1.00 in. 0 0.00K Onslow County 06/29/2011 Hail 0.75 in. 0 0.00K Onslow County 06/29/2011 Hail 0.88 in. 0 0.00K HAWKSIDE 07/24/2011 Hail 0.88 in. 0 0.00K HAWKSIDE 07/24/2011 Hail 1.00 in. 0 0.00K Camp Lejeune 08/12/2011 Hail 1.00 in. 0 0.00K ERVINTOWN 09/30/2011 Hail 0.75 in. 0 0.00K Haw Branch 02/24/2012 Hail 1.00 in. 0 0.00K HAWKSIDE 03/25/2012 Hail 1.00 in. 0 0.00K BROCKS 03/30/2012 Hail 0.75 in. 0 0.00K HUFFMANTOWN 03/30/2012 Hail 1.00 in. 0 0.00K Bell Fork 05/05/2012 Hail 0.88 in. 0 0.00K JARMANTOWN 07/01/2012 Hail 1.75 in. 0 0.00K STARLING 03/22/2014 Hail 0.75 in. 0 0.00K DIXON 03/22/2014 Hail 1.00 in. 0 0.00K STARLING 03/22/2014 Hail 1.75 in. 0 0.00K HUBERT 03/22/2014 Hail 1.00 in. 0 0.00K SHELL ROCK LNDG 03/22/2014 Hail 0.75 in. 0 0.00K Swansboro 03/22/2014 Hail 1.75 in. 0 0.00K Totals: 0 0.00K
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 16 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
Figure 4.5: Hail Occurrences in Onslow County
4.3.4. Probability of Future Occurrences
Given the history of occurrences and the natural climatic patterns around Southeastern North Carolina the probability of future occurrences for severe thunderstorm events in Onslow County is high. This will result in the probability of future hail occurrences in Onslow County remaining high.
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4.4.Hurricane & Coastal Storm (includes Nor’easter)
4.4.1. Background
Hurricanes, coastal storms and Nor’easter are all forms of cyclones. Hurricanes and coastal storms are a tropical cyclone that is a rotating, organized system of cloud and thunderstorms that originate in tropical or subtropical waters and have closed low-level circulation. Tropical cyclones in the northern hemisphere rotate counterclockwise. Tropical cyclones are warm-core, low pressure systems that thrive on the warmer airs and warmer waters. There are four primary types of tropical cyclones:
Tropical Depression – max sustained winds of 38mph or less Tropical Storm – max sustained winds of 39-73mph Hurricane – max sustained winds of 74mph and higher. Major Hurricane – max sustained winds of 111mph or higher. (Category 3, 4 and 5).
A Nor’easter is a form of a cyclone that forms, typically, along the upper East Coast of the United States and Canada. Nor’easters also rotate counterclockwise. Nor’easters differ from tropical cyclones in that nor’easters are cold-core, low pressure systems, meaning they thrive on colder temperatures and waters.
The primary damaging forces associated with these types of storms include high-level sustained winds, heavy precipitation, tornadoes, storm surge, coastal erosion, and flooding. Nor’easters may also include snow and blizzard conditions due to the colder air temps.
Hurricane seasons runs from June 1 until November 30th each year. The peak period for named storms runs from around mid-August until late October. The key
Tropical cyclones can develop in the Gulf of Mexico, the Caribbean Sea, the Pacific and Atlantic Oceans. They are born in moist tropical air. About every four to five days, a tropical wave of low pressure moves along with westerly winds. In developing tropical cyclones, strong thunderstorms occur. Air pressure drops at the surface of these storms. This low pressure attracts warm moist air from the ocean's surface. The Coriolis force causes the resulting low-level winds to spiral in a counterclockwise direction around the center of the low in the Northern Hemisphere. Sinking air at the center clears the tropical cyclone of clouds and forms the "eye”, but an eye is not necessary for a tropical cyclone to become a hurricane. Falling surface pressure can occur only if air mass is removed from the circulation center. This is accomplished by wind flowing away from the circulation in the upper atmosphere.
When maximum sustained winds reach or exceed 39 miles per hour, the system is designated a tropical storm, given a name, and is closely monitored by the National Hurricane Center in Miami, Florida. When sustained winds reach or exceed 74 miles per hour the storm is deemed a hurricane. Hurricane intensity is further classified by the Saffir-Simpson Hurricane Wind Scale (Table 4.6) which rates hurricane intensity on a scale of 1 to 5, with 5 being the most intense.
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Table 4.6: Saffir-Simpson Hurricane Wind Scale (2012 revision) Storm Sustained Damage Types of Damages Category Winds Level Very dangerous winds will produce some damage: Well-constructed frame 74-95 mph homes could have damage to roof, shingles, vinyl siding and gutters. Large 1 64-82 kt MINIMAL branches of trees will snap and shallowly rooted trees may be toppled. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days. Extremely dangerous winds will cause extensive damage: Well-constructed 96-110 mph frame homes could sustain major roof and siding damage. Many shallowly rooted 2 83-95 kt MODERATE trees will be snapped or uprooted and block numerous roads. Near-total power
loss is expected with outages that could last from several days to weeks. Devastating damage will occur: Well-built framed homes may incur major damage 111-129 mph or removal of roof decking and gable ends. Many trees will be snapped or 3 96-112 kt EXTENSIVE uprooted, blocking numerous roads. Electricity and water will be unavailable for
several days to weeks after the storm passes. Catastrophic damage will occur: Well-built framed homes can sustain severe 130-156 mph damage with loss of most of the roof structure and/or some exterior walls. Most 4 113-136 kt EXTREME trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months Catastrophic damage will occur: A high percentage of framed homes will be 157 mph+ destroyed, with total roof failure and wall collapse. Fallen trees and power poles 5 137 kt + CATASTROPHIC will isolate residential areas. Power outages will last for weeks to possibly months.
Most of the area will be uninhabitable for weeks or months
The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 categorization based on the hurricane's intensity at the indicated time. The scale – originally developed by wind engineer Herb Saffir and meteorologist Bob Simpson. The scale provides examples of the type of damage and impacts in the United States associated with winds of the indicated intensity. In general, damage rises by about a factor of four for every category increase. The maximum sustained surface wind speed associated with the cyclone is the determining factor in the scale. The 2012 revision to the scale was designed to help reduce public confusion about the impacts associated with the various hurricane categories as well as to provide a more scientifically defensible scale. As a result, the storm surge ranges, flooding impact and central pressure statements were removed from the scale and only peak winds were employed.
As mentioned above a Nor’easter is a type of cyclone that forms in the north eastern area of North America. These storms can cause similar damages to the tropical cyclones and are most notably different because of their snowfall amounts and the time of year. There are two main components of the Nor’easter: 1) a Gulf-Stream low pressure system that gathers warm air and moisture and is pulled up the coast by the northeasterly winds of the storm and 2) an Arctic high-pressure system that brings in cold, arctic air blowing down from Canada. Nor’easters tend to be much larger in scale than hurricanes and also much slower. With prolonged increased winds speeds and stronger surfs coastline damages are a greater concern. The most common categorical scale used to describe Nor’easters is the Dolan-Davis Nor’Easter Intensity Scale as seen below in Table 4.7.
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 19 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
Table 4.7: Dolan-Davis Nor’easter Intensity Scale Storm Class Beach Erosion Dune Erosion Over wash Property Damage
1 (Weak) Minor changes None No No
Modest; mostly to lower 2 (Moderate) Minor No Modest beach
Erosion extends across Loss of many structures 3 (Significant) Can be significant No beach at local level
Severe beach erosion/ Severe dune erosion/ Loss of many structures 4 (Severe) On low beaches recession destruction at community-scale Dunes destroyed over Massive in sheets Extensive at regional- 5 (Extreme) Extreme beach erosion extensive areas and channels scale; millions of $ Source: NC Division of Emergency Management, Local Hazard Mitigation Planning Manual
4.4.2. Location and Spatial Extent
Hurricanes and coastal storms threaten the entire Eastern Coast and Gulf Coast region of North America. Coastal areas are most directly exposed to the dangers of these types of storms however, depending on the diameter and the track of the storm, their impacts may be felt quite far inland. Onslow County is situated along the coast of North Carolina and will remain susceptible to the hazards of hurricanes, coastal storms and Nor’easters. All jurisdictions and areas of the county will be at risk to hazards such as flooding, tornadoes, and wind damage however only the coastal areas will be susceptible to storm surge, wave action and coastal erosion.
4.4.3. Historical Occurrences
North Carolina has had an extensive hurricane history dating back to colonial times. During the nineteenth century, storms occurred in 1837, 1846, 1856, 1879, 1883, and 1899. During the 1950s, the State was ravaged by several hurricanes, including Hazel, Connie, Diane, and Ione. The years 1960 thru 1990 saw a decrease in land falling hurricanes, with the exception of Hurricane Donna in 1960. The last decade has seen Hurricanes Hugo (1989), Emily (1993), Opal (1995), Bertha (1996), Fran (1996), Bonnie (1998), Dennis (1999), Floyd (1999), Irene (1999), Isabel (2003), Alex (2004), and Ophelia (2005), all leaving their mark on the State. However, these storms had varying impacts on Onslow County. Hurricanes passing thru Onslow County have produced floods as well as extensive structural damage. The following table provides a brief description of several hurricanes, which significantly impacted Onslow County.
According to NOAA historical track records, 104 hurricanes or tropical storm tracks have passed within a 75 mile radius of Jacksonville and Onslow County since 1842. This includes no (0) category 5, two (2) category 4, five (5) category 3, eleven (11) category 2, twenty-six (26) category 1, fifty-one (51) tropical storms and one (1) sub-tropical storm. Of the 104 recorded events 16 were direct hits in Onslow County and 24 have passed through Onslow County resulting in approximately $611 million in property damages and $56 million in crop damages (in 2014 dollars). Table 4.8 provides the historical occurrences of hurricanes and coastal storms providing name (if available), date, category, and max winds speeds (as recorded within 75 miles of Onslow County). Figure 4.6 provides a visual track of each of these storms in relation to Onslow County.
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 20 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
Table 4.8: Significant Hurricane History Storm Tacks within 75 Miles of Onslow County (1848-2014) Name of Storm Date of Occurrence Storm Category Max Wind Speeds (kts) Not Named 8/25/1851 Tropical Storm 40 Not Named 08/28/1852 Tropical Storm 40 Not Named 10/10/1852 Tropical Storm 50 Not Named 08/19/1856 Tropical Storm 50 Not Named 09/01/1856 Tropical Storm 50 Not Named 09/13/1857 Category 2 90 Not Named 09/27/1861 Category 1 70 Not Named 11/02/1861 Category 1 70 Not Named 09/18/1863 Tropical Storm 60 Not Named 10/24/1872 Category 1 70 Not Named 09/28/1874 Category 1 80 Not Named 09/17/1876 Category 1 80 Not Named 10/11/1878 Tropical Storm 50 Not Named 10/23/1878 Category 2 90 Not Named 08/18/1879 Category 3 100 Not Named 09/09/1880 Category 1 70 Not Named 09/09/1881 Category 1 80 Not Named 09/22/1882 Tropical Storm 60 Not Named 10/12/1882 Category 1 70 Not Named 09/11/1883 Category 1 70 Not Named 08/25/1885 Category 1 80 Not Named 10/11/1888 Tropical Storm 60 Not Named 06/16/1893 Tropical Storm 50 Not Named 10/04/1893 Tropical Storm 40 Not Named 09/27/1894 Tropical Storm 60 Not Named 10/09/1894 Tropical Storm 60 Not Named 09/22/1897 Tropical Storm 60 Not Named 07/11/1901 Tropical Storm 40 Not Named 09/18/1901 Tropical Storm 35 Not Named 07/30/1908 Category 1 70 Not Named 09/01/1908 Tropical Storm 45 Not Named 10/20/1910 Tropical Storm 60 Not Named 09/03/1913 Category 1 75 Not Named 05/16/1916 Tropical Storm 35 Not Named 09/06/1916 Tropical Storm 45 Not Named 08/24/1918 Category 1 65 Not Named 09/18/1928 Tropical Storm 60 Not Named 09/15/1932 Tropical Storm 35 Not Named 08/01/1944 Category 1 80 Not Named 06/05/1945 Tropical Storm 60 Not Named 07/05/1946 Tropical Storm 40 Hazel 10/15/1954 Category 3 110 Connie 08/11/1955 Category 2 90 Diane 08/17/1955 Category 1 75 Ione 09/19/1955 Category 3 100 Helene 09/27/1958 Category 4 115 Brenda 07/30/1960 Tropical Storm 50 Donna 09/12/2960 Category 2 95
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 21 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
Not Named 09/14/1961 Tropical Storm 35 Dora 09/13/1964 Tropical Storm 45 Isabell 10/16/1964 Category 1 80 Not Named 06/16/1965 Tropical Storm 40 Gladys 10/19/1968 Category 1 75 Doria 08/27/1971 Tropical Storm 55 Ginger 09/30/1971 Category 1 75 Agnes 06/21/1972 Tropical Storm 40 Dennis 08/20/1981 Tropical Storm 55 Diana 09/12/1984 Category 4 115 Kate 11/22/1985 Tropical Storm 50 Charley 08/17/1986 Category 1 65 Arthur 06/19/1996 Tropical Storm 40 Bertha 07/12/1996 Category 2 90 Fran 09/05/1996 Category 3 100 Bonnie 08/26/1998 Category 3 100 Dennis 08/30/1999 Category 2 90 Floyd 09/16/1999 Category 2 90 Helene 09/23/2000 Tropical Storm 35 Kyle 10/11/2002 Tropical Storm 35 Charley 08/14/2004 Category 1 65 Ophelia 09/14/2005 Category 1 75 Ernesto 08/31/2006 Tropical Storm 60 Gabrielle 09/09/2007 Tropical Storm 50 Cristobal 07/19/2008 Tropical Storm 45 Hanna 09/06/2008 Tropical Storm 60 Irene 08/27/2011 Category 1 75 Arthur 07/03/2014 Category 2 100 Source: National Oceanic and Atmospheric Administration, National Coastal Services Center
Figure 4.6: Historical Storm Tracks in Onslow County
Source: National Oceanic and Atmospheric Administration, National Coastal Services Center
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Some of the more notable hurricanes to impact Onslow County are:
July 12, 1996: Hurricane Bertha The eye of Bertha passed 12 miles west of downtown Jacksonville making a northward track through the western portions of Onslow County. Berth caused approximately $42 million in damges and resulted in one fatality and 10 storm related injuries. Most wind measurements were around 90-99mph with gusts of 108mph recorded at MCAS New River. Damages in Onslow County included storm surge, flooding, beach erosion, roof damage, and fallen trees. Heaviest damage was in Topsail Beach and Onslow County where 199 structures were destroyed (117 of which were mobile homes). Rainfall of up to 14 inches was reported at Hoffman Forest, also just east of where the center made landfall.
September 5, 1996: Hurricane Fran The eye of Hurricane Fran passed within 43 miles of Jacksonville, NC and brought hurricane force winds to all of Onslow County. Storm surges of 10-12 feet and winds over 100mph recorded at North Topsail Beach. Approximately 90% of the homes on North Topsail Beach were damaged or destroyed. Damages in Onslow County exceeded $500 million and over 6,688 structures were damaged or destroyed countywide. A total of 409 business and 4,926 homes were included in these damages. Damages to schools totaled approximately $1.6 million. Dune erosion ranged from 5-20 feet along the North Carolina coastline. Torrential rains resulted in flooding throughout Onslow County with over 1 foot of water on Highway 24 in Richlands. Many bridges in the county suffered damages as a result. Some notable facts (NC Emergency Management):
Debris removal costs: $15 million Agricultural losses: $35 million Forestry losses: $30 million Temporary housing payments: $3,317 (2,034 applicants) Individual/family grants: $$2,048,317 (739 applicants) SBA Loans: $$13,214,500 (478 applicants) Public Assistance: $17,229,596 (193 applicants) Economic impact: $347 million Deaths: 4 Injuries: 4
August 26, 1998: Hurricane Bonnie The eye of slow-moving Hurricane Bonnie made landfall at Cape Fear during the late afternoon and moved up the coast, with the stronger east side of the storm remaining offshore. Wind gusts were generally around 100 MPH along the coast and lighter inland. At the Wilmington Airport, gusts reached 62 MPH. Rainfall amounts were around 11 inches, causing ponding of water and flooding across county. Storm surge was 7 to 9 feet, with most barrier island overwash from the sound side, not the ocean side. A Federal Disaster was declared. Onslow County had approximately $2 million in damages.
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September 15, 1999: Hurricane Floyd Hurricane Floyd, with wind gusts around 100 mph, affected five North Carolina counties, causing downed trees and power outages. The eye of the hurricane passed directly over Onslow County passing within 1 mile of downtown Jacksonville. Ocean storm surge was 9 to 10 feet, inundating barrier islands and causing extensive dune erosion on North Topsail Beach. Record rainfall distinguished Floyd – with Jacksonville receiving around 8.26”, causing widespread flooding.
September 18, 2003: Hurricane Isabel The eye of Hurricane Isabel passed within 75 miles of downtown Jacksonville however, the hurricane force winds extended out to almost 90 miles from the center track of the storm. The storm had a northwest track making landfall in Drum Inlet in Carteret County placing the entire north eastern portion of Onslow County within the hurricane force winds.
September 14, 2005: Hurricane Ophelia At 11:00 am on September 14th, Category 1 Ophelia was centered about 25 miles southeast of Cape Fear. The storm mainly affected Brunswick, Pender, and New Hanover counties. The large eyewall (50 miles in diameter) however, allowed hurricane force winds to grave North Topsail Beach. There were unofficial reports of wind gusts to 75mph on North Topsail Beach. Average rainfall over Onslow County was around 5.2 inches. Damage over the area was mainly minor roof damage and flooding. Cosmetic and minor damage to beach homes was reported throughout the affected area. Beach erosion was also a problem. Damage to the area and the cost for clean up would be approximately $35 million, primary for removing debris.
August 24, 2011: Hurricane Irene Irene made landfall near Cape Lookout, North Carolina with an intensity of 75 kt, producing category 1 hurricane-force winds within a swath primarily to the east of the center over the North Carolina sounds and the Outer Banks. Hurricane forces winds extended 43 miles from the center of the track and the eye passed within 50 miles of downtown Jacksonville. Storm surges were recorded at around 4 foot in Surf City, NC and wind gusts of 50-60mph. A total of approximately 12 inches of rainfall was recorded. A total of 635 residences and 10 businesses suffered damages. There was approximately $17 million in damages to agriculture and about 233,000 cubic yards of debris costing around $2.8 million to remove. Countywide, including the municipalities’ damages to government property totaled around $2.5 million. The total cost of the storm in Onslow County was approximately $29 million (2011 dollars). Onslow County had 1 reported death as a secondary result of the storm.
Analysis of nor'easter frequency by researchers reveals fewer nor'easters during the 1980s. However, the frequency of major nor'easters (class 4 and 5 on the Dolan-Davis scale) has increased in recent years. In the period 1987 to 1993, at least one class 4 or 5 storm has occurred each year along the Atlantic seaboard of the United States, a situation duplicated only once in the last 50 years.
A number of notable nor'easters have impacted North Carolina in recent decades, including the Ash Wednesday Storm of March 1962, but they were typically only of local concern. One exception to this was the nor'easter of late October and early November 1990, which loosened a dredge barge that struck and destroyed approximately five roadway segments of the Bonner Bridge in Dare County. Another Nor’easter struck the Outer Banks on Halloween, 1991, causing substantial beach erosion.
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4.4.4. Probability of Future Occurrences
North Carolina's geographic location on the Atlantic Ocean and its proximity to the Gulf Stream makes it prone to hurricanes. In fact, North Carolina has experienced the fourth greatest number of hurricane landfalls of any State in the twentieth century (trailing Florida, Texas, and Louisiana). Figure 4.7 shows what the chance is that a tropical storm or hurricane will affect an area sometime during the Atlantic hurricane season. This illustration was created by the National Oceanic and Atmospheric Administration’s Hurricane Research Division using data from 1944 to 1999 and counting hits when a storm or hurricane was within approximately 100 miles (165 km) of each location. According to this figure, Onslow County (located at approximately 34N, 77N) is in an area with an annual probability of a named storm between 36 and 48 percent.
Although nor'easters are more diffuse and less intense than hurricanes, they occur more frequently and cover larger areas and longer coastal reaches at one time. As a result, the likelihood of a Nor'easter occurring in Onslow County is much higher than that of a hurricane.
Figure 4.7: Empirical Probability of a Hurricane
Source: NOAA: National Hurricane Center
The National Hurricane Center, after studying the average impact rate over 100 years, developed a “rate of return” probability for hurricanes (>= 64kts). Based on the probability rating in a 100 year period Onslow County can expect a hurricane within 50 nautical miles of its coast 15 times, or a probability of return once every 7 years. These numbers are a probability and hurricanes can strike more often than once every seven years. The probability of storm occurrences will vary significantly based on the return interval for different categories of magnitude. The probability of less intense storms is higher than the more intense storms.
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4.5.Tornado
4.5.1. Background
A tornado is a narrow, violently rotating column of air that extends from the base of a thunderstorm to the ground. It is hard to see a tornado until it forms condensation within the funnel made of water droplets, dust or debris. Tornadoes are the most violent of all atmospheric storms. While tornadoes occur throughout the world the United States averages around 1,200 a year, one of the highest concentrations in the world.
Tornados form primarily from supercell thunderstorms, those with well defined radar circulation. A rotating updraft is key to the development of the supercell and eventually the tornado itself. Often winds at ground level are slowed by friction while winds in the upper levels of the supercell move much faster. Rising air, often warm and moist, begins to develop the “tube” which then creates vertical rotation. This vertical updraft fed by the warm moist air can lead to the formation of the tornado. Tornadoes can also form in non-supercell thunderstorms, hurricanes and other coastal storms. The National Weather Service reports that on average only 20% of supercell storms will develop tornadic activity. Damages caused by tornadoes are usually the result of the high wind velocities and wind-blown debris. Lightening and hail usually accompany these storms and can also result in damages. While the National Weather Service’s has methods of measure the winds, most often these are in the slower tornadoes. The highest radar motion detected was over 300mph.
On average, tornadoes kill about 60 people per year, mostly from falling or flying debris. According to the NOAA Storm Predication Center Oklahoma City has the highest concentration of tornado activity for a city and Kansas, Florida, Oklahoma, Iowa, and Illinois have the highest concentration for states. Figure 4.8 show an average annual tornado per year per 10,000 square miles per state. North Carolina, and Onslow County, is in an area that received approximately 1-6 tornadoes per average year.
Waterspouts are weak tornadoes that form over water and are most common along the Gulf Coats and Southeastern United States. Waterspouts will occasionally move inland, becoming a tornado that can cause damage and injury. Most waterspouts will dissipate over open water causing the highest threat to marine and boating interests. Typically, waterspouts are weak and short lived and most go unreported unless they cause damages.
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Figure 4.8: Average Annual Tornadoes per 10K square miles per State
Source: National Weather Services, Storm Prediction Center
Peak tornado season in the Southeast is March through May and in the northern states it runs late spring through early summer. They can occur at any time of the day, but are most likely to occur between 3pm and 9pm. Structures of light construction, such as mobile homes, are at greatest risk for damages from tornadoes.
A tornado is reported by its magnitude according to the Enhanced Fujita Scale (EF Scale). The EF Scale became operational on February 1, 2007 replacing the original Fujita Scale. The scale assigns a “rating” based on estimated wind speeds and related damage. After a tornado occurs, field surveyors will compare a list of Damage Indicators (DI) and degrees of damage (DoD) to help estimate the range of wind speeds that were likely produced. Table 4.9 shows the Enhanced Fujita Scale with probable associated damages.
Table 4.9: Enhanced Fujita Scale EF Scale Rating 3 Second Gust (mph) Expected Types of Damages Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted 0 65-85 trees; damages to sign boards. The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile 1 86-110 homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed. Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars 2 111-135 pushed over; large trees snapped or uprooted; light object missiles generated. 3 136-165 Roof and some walls torn off well-constructed houses; trains overturned; most trees in
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forest uprooted. Well-constructed houses leveled; structures with weak foundations blown off some 4 166-200 distance; cars thrown and large missiles generated. Strong frame houses lifted off foundations and carried considerable distances to 5 Over 200 disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-enforced concrete structures badly damaged. Source: National Weather Service
4.5.2. Location and Spatial Extent
Tornadoes can occur throughout the state of North Carolina. When compared with other states North Carolina currently ranks 20th in the nation for number of tornado events and 17th for tornado fatalities. These figures were derived by FEMA for a 60 year study period running from 1950-2010. Figure 4.10 shows total tornado occurrences for all of North Carolina, by county, from 1950-2003. Onslow County has recorded a total of 33 tornadoes. Figure 4.10: Tornado Occurrences in North Carolina by County
Source: State Climate Office of North Carolina
4.5.3. Historical Occurrences
According to the National Climatic Data Center there have been a total of 44 recorded tornadoes and 1 recorded waterspout in Onslow County since 1950. It is highly likely that small tornadoes and many waterspouts have gone unrecorded during this time period. Tornadoes have caused an estimated $15.42 million in damages and resulted in three deaths and 59 injuries. Table 4.9 provides of list of reported tornadoes and Table 4.10 provides a list of recorded waterspouts. The magnitudes of tornadoes are listed as F0-F5 for the original Fujitsu Scale (all tornadoes before February 1, 2007) and EF0-EF5 for the Enhanced Fujitsu Scale (all tornadoes after February 1, 2007). Figure 4.11 shows a visual representation of impact locations and their recorded magnitudes.
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Table 4.9: Tornado Events in Onslow County
Location Date Magnitude Death / Injuries Property Damage
ONSLOW CO. 05/30/1955 F1 0/0 2.50K
ONSLOW CO. 08/01/1961 F1 0/0 250.00K
ONSLOW CO. 01/20/1963 F1 0/0 25.00K
ONSLOW CO. 05/20/1963 F1 0/0 2.50K
ONSLOW CO. 10/24/1972 F2 0/0 25.00K
ONSLOW CO. 06/27/1977 F0 0/0 0.25K
ONSLOW CO. 04/19/1978 F2 0/3 250.00K
ONSLOW CO. 03/14/1986 F0 0/0 25.00K
ONSLOW CO. 03/14/1986 F1 0/0 25.00K
ONSLOW CO. 07/02/1986 F2 3/10 250.00K
ONSLOW CO. 11/10/1987 F0 0/0 25.00K
ONSLOW CO. 06/09/1988 F1 0/2 2.500M
ONSLOW CO. 02/21/1989 F1 0/0 250.00K
ONSLOW CO. 06/29/1990 F0 0/0 0.00K
ONSLOW CO. 08/02/1991 F0 0/0 0.00K
ONSLOW CO. 08/02/1991 F1 0/1 0.00K
ONSLOW CO. 08/02/1991 F0 0/0 0.00K
ONSLOW CO. 08/18/1991 F0 0/0 0.00K
Sneads Ferry 10/28/1995 F0 0/0 5.00K
Camp Lejeune 10/28/1995 F0 0/0 50.00K
Hubert 10/28/1995 F0 0/0 0.50K
JACKSONVILLE 10/08/1996 F1 0/0 60.00K
DEPPE 04/21/1997 F0 0/0 0.00K
RICHLANDS 04/15/1999 F1 0/7 2.000M
SNEADS FERRY 09/15/1999 F0 0/0 0.00K
JACKSONVILLE 10/17/1999 F0 0/0 0.00K
RICHLANDS 03/16/2000 F0 0/0 20.00K
CATHERINE LAKE 05/21/2000 F0 0/0 0.00K
JACKSONVILLE 02/22/2003 F0 0/0 0.00K
JACKSONVILLE 07/02/2003 F1 0/0 60.00K
HALF MOON 07/02/2003 F0 0/0 0.00K
RICHLANDS 07/02/2003 F0 0/0 0.00K
SWANSBORO 06/22/2004 F0 0/0 10.00K
RICHLANDS 08/13/2004 F0 0/0 25.00K
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JACKSONVILLE 08/14/2004 F0 0/0 10.00K
JACKSONVILLE 04/17/2006 F0 0/0 0.00K
JACKSONVILLE 07/23/2006 F0 0/0 0.00K
SNEADS FERRY 08/31/2006 F0 0/0 0.00K
BELGRADE 05/11/2008 EF2 0/0 150.00K
MORTON FORK 05/11/2008 EF0 0/0 0.00K
ONSLOW BEACH 09/25/2008 EF0 0/0 0.00K
MIDWAY PARK 05/07/2009 EF0 0/0 0.00K
MIDWAY PARK 04/16/2011 EF3 0/30 9.400M
CAMP LEJEUNE JCT 06/10/2013 EF1 0/0 0.50K Totals: 3/59 15.421M
Source: National Climatic Data Center Table 4.10: Waterspout Events in Onslow County
Location Date Magnitude Death / Injuries Property Damage
NORTH TOPSAIL BEACH 09/10/1997 0/0 0.00K
Totals: 0/0 0.00K Source: National Climatic Data Center
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Figure 4.11: Location History and Magnitude of Tornadoes in Onslow County
4.5.4. Probability of Future Occurrences
Onslow County will continue to have a high susceptibility to tornadoes. While the majority of these events have been historically small in terms of size, intensity (27 of 44 are classified as F0/EF0), and duration they will continue to pose a significant threat to the County as a whole.
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4.6. Winter Storm
4.6.1. Background
Winter storms can range from a moderate snow over a few hours to a blizzard with blinding, wind-driven snow that lasts for several days. Many winter storms are accompanied by dangerously low temperatures and sometimes by strong winds, icing, sleet, and freezing rain. Some winter storms may affect the entire state or be geographically local to the southeastern coastal plains.
Sleet is formed when raindrops freeze to for an ice pellet before reaching the ground where it will bounce but does not usually stick to objects. However, sleet can accumulate, like snow, and create hazardous driving conditions. Freezing rain is rain that falls to the ground where the temperature is below freezing and allows the rain to create a glaze of ice on roadways. An ice storm occurs when freezing rain falls and freezes upon impact with objects and creates hazards for power lines, roads, and trees.
A freeze event is marked by low temperatures below the freezing point (thirty-two degrees Fahrenheit). Freeze events are particularly dangerous. Exposure to freeze events Snow accumulation on the roadways in Jacksonville (photo can result in wind chill, hypothermia and frost bite. More from NOAA) than 50% of the cold injuries occur in people over the age of 60 and more than 75% are males. Around 20% of cold injuries occur in the home. In the south, near freezing temperatures are considered extreme cold. Freezing temperatures can be a danger to agricultural production especially when freezes occur late in the season and persist over an extended period of time.
4.6.2. Location and Spatial Extent
Onslow County is located in a region that is not particulary susceptible to winter storm and freeze events. However, when such events do occur the effects will often be felt much greater and over a widespread area. The inland areas, particularly the northwest portions of Onslow County, are at slightly higher risk to these storms due to naturally warmer air temperatures closer to the ocean. Extreme temperatures will most often create greater effects on the elderly and homeless populations, but larger snowstorms may have widespread effects.
4.6.3. Historical Occurrences
The National Climatic Data Center has documented twenty-four winter storm events in Onslow County. These events have resulted in approximately 35 injuries and $145 thousand in property damage.
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Table 4.11: Winter Weather Events in Onslow County Date of Death/ Property Damages Crop Damages
Location Type Magnitude Occurrence Injury (2014 dollars) (2014 dollars) Onslow County 02/03/1996 Winter Storm 0/35 45.00K 0.00K Onslow County 02/10/1997 Winter Storm 0/0 0.00K 0.00K Onslow County 01/19/1998 Winter Storm 0/0 0.00K 0.00K Onslow County 01/27/1998 Winter Storm 0/0 0.00K 0.00K Onslow County 02/03/1998 Winter Storm 0/0 100.00K 0.00K Onslow County 02/17/1998 Winter Storm 0/0 0.00K 0.00K Onslow County 03/02/1998 Sleet 0/0 0.00K 0.00K Onslow County 03/11/1998 Cold/Wind Chill 0/0 0.00K 0.00K Onslow County 01/03/2002 Winter Storm 0/0 0.00K 0.00K Onslow County 01/23/2003 Winter Storm 0/0 0.00K 0.00K Onslow County 01/09/2004 Winter Weather 0/0 0.00K 0.00K Onslow County 01/25/2004 Winter Storm 0/0 0.00K 0.00K Onslow County 01/26/2004 Winter Storm 0/0 0.00K 0.00K Onslow County 02/16/2004 Winter Weather 0/0 0.00K 0.00K Onslow County 02/26/2001 Winter Weather 0/0 0.00K 0.00K Onslow County 03/23/2004 Frost/Freeze 0/0 0.00K 0.00K Onslow County 12/20/2004 Winter Weather 0/0 0.00K 0.00K Onslow County 12/26/2004 Winter Storm 0/0 0.00K 0.00K Onslow County 01/20/2009 Heavy Snow 0/0 3 inches 0.00K 0.00K Onslow County 02/12/2010 Heavy Snow 0/0 8 inches 0.00K 0.00K Onslow County 12/26/2010 Heavy Snow 1/0 4 inches 0.00K 0.00K Onslow County 01/10/2011 Heavy Snow 0/0 5 inches 0.00K 0.00K Onslow County 01/28/2014 Winter Storm 0/0 2 inches 0.00K 0.00K Onslow County 02/11/2014 Winter Storm 0/0 4 inches 0.00K 0.00K Totals: 1/35 145.00K 0.00K
4.6.4. Probability of Future Occurrences
The entire State has a likelihood of experiencing severe winter weather. The threat varies by location and by type of storm. Coastal areas typically face their greatest threat from nor'easters and other severe winter coastal storms. These storms can contain strong waves and result in extensive beach erosion and flooding. Freezing rain and ice storms typically occur once every several years at coastal locations and severe snowstorms have been recorded occasionally in coastal areas. Out of the eight (8) total climate divisions in North Carolina, Onslow County's climate division (#6) ranked eighth in terms of average one-day extreme snowfall. Extreme Average Snowfall by Climate Division provides a summary of average one-day extreme snowfall for each North Carolina climate division
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The probability of future winter storm events in Onslow County remains moderate. Figure 4.12 shows the annual mean snowfall hazard for the U.S.
Figure 4.12: Average Annual Snowfall for the U.S.
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GEOLOGIC
4.7. Earthquake
4.7.1. Background Information
Earthquakes are geologic events that involve movement or shaking of the Earth's crust. Earthquakes are usually caused by the release of stresses accumulated because of the rupture of rocks along opposing fault planes in the Earth's outer crust. These fault planes generally follow the outlines of the continents. Earthquakes can result from crustal strain, volcanoes, landslides, or the collapse of caverns. Earthquakes can affect hundreds of thousands of square miles causing damages to property, loss of life and disruption of social and economic infrastructure in the affected area.
Most earthquakes occur as a result of the release of accumulated stresses. These stresses build up when two opposing tectonic plates of the Earth’s crust become lodged on one another. The areas where these blocks meet are known as fault lines. The areas of greatest instabilities occur at the perimeters of the lines where two plates are moving in opposite directions and at opposite speeds. When the plates become locked together energy begins to accumulate. Eventually, this energy will exceed the rock’s strength and a rupture will occur. The rocks on both sides of the fracture will snap releasing the stored energy which generates seismic waves.
Earthquakes may last only a few seconds or may continue for up to several minutes. They can occur at any time of the day or night and at any time of the year. Although thousands of earthquakes occur in the United States each year, most are too small to affect us. Earthquakes of larger magnitude, however, which release more energy during fault ruptures, can be hazardous, exposing us to the risk of harm or loss. The primary risk to people is what the ground motions can do to the natural and man-made environments.
Aerial view of collapsed sections of the Cypress The level of damage depends upon the amplitude and duration of the viaduct of Interstate Highway 880. Oakland, shaking, which are directly related to the earthquake size, distance California. Photographer: H.G. Wilshire, USGS. from the fault, site and regional geology. Other damaging earthquake effects include landslides, the down-slope movement of soil and rock (mountain regions and along hillsides), and liquefaction, in which ground soil loses the ability to resist shear and flows much like quick sand. In the case of liquefaction, anything relying on the substrata for support can shift, tilt, rupture or collapse.
Magnitude and Intensity measure different characteristics of earthquakes. Magnitude measures the energy released at the source of the earthquake. Magnitude is determined from measurements on seismographs. Intensity measures the strength of shaking produced by the earthquake at a certain location. Intensity is determined from effects on people, human structures, and the natural environment. Each unit increase in magnitude typically corresponds to a ten-fold increase in wave amplitude, or a 244-fold increase in energy intensity.
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Table 4.12 provides a comparison of the magnitude scales and intensity scales with associated potential impacts as identified by the Modified Mercalli Scale.
Table 4.12: Magnitude and Intensity Scales Typical Maximum Magnitude Modified Mercalli Abbreviated Modified Mercalli Intensity Scale Intensity 1.0-3.0 I I. Not felt except by a very few under especially favorable conditions. II. Felt only by a few persons at rest, especially on upper floors of buildings III. Felt quite noticeably by persons indoors, especially on upper floors of 3.0-3.9 II-III buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck. Duration estimated IV. Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked 4.0-4.9 IV-V noticeably. V. Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop. VI. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight. 5.0-5.9 VI-VII VII. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken. VIII. Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, 6.0-6.9 VII-IX walls. Heavy furniture overturned. IX. Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations. X. Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent 7.0 and XI. Few, if any (masonry) structures remain standing. Bridges destroyed. VII or higher higher Rails bent greatly. XII. Damage total. Lines of sight and level are distorted. Objects thrown into the air Source: United States Geological Society
4.7.2. Location and Spatial Extent
In North Carolina, earthquake epicenters are generally concentrated in the active Eastern Tennessee Seismic Zone. North Carolina is affected by both the Charleston Fault in South Carolina and the New Madrid Fault in Missouri. Both of these faults have generated earthquakes measuring greater than a magnitude of 8 during the last 200 years. Onslow County is most at risk from the Charleston fault, as noted in the Great Charleston Earthquake of 1886. Figure 4.13 shows earthquake activity in the North Carolina region. The picture indicates that Onslow County, in the Coastal Plain, resides in a band of uniformly limited seismic risk.
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4.13: Earthquake Epicenters in North Carolina and Portions of Adjacent States (1698-1997)
Source: North Carolina Department of Environment and Natural Resources, Division of Energy, Mineral and Land Resources.
4.7.3. Historical Occurrences
Earthquakes while relatively infrequent are not uncommon in North Carolina. In 2011 Onslow County experienced tremors as a result of a 5.8 magnitude earthquake centered in Mineral, Virginia. There were no recorded damages in Onslow County. Local records and the NOAA: National Geophysical Data Center there is no recorded events of earthquake damages in Onslow County.
4.7.4. Probability of Future Occurrences
The probability of Earthquakes events in Onslow County is moderated to low and should face only minimal effects from seismic activity.
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4.8. Landslide and Sinkhole
4.8.1. Background
The term landslide includes a wide range of ground movement, typically driven by gravity and resulting in the downward and outward movement of soil, rock and vegetation. Landslides occur in every state and U.S. Territories and can be triggered by both natural and human-caused changes in the environment including heavy rains, rapid snow melt, erosion, earthquakes, volcanic eruptions and changes in groundwater levels.
There are several types of landslides: rotational slide, transitional slide, block slide, fall, topple, debris flow, debris avalanche, earth flow, creep and lateral spreads. Each of the slides (rotational, transitional and block) refer to only mass movements, where there is a distinct zone of weakness that separates the slide material from the more stable material underneath. Falls are described as abrupt movement of masses of geologic material that become detached from steep slopes or cliffs. Separation in falls occurs along joints or fractures and movement occurs by free-fall.
A Topple is distinguished by a forward rotational unit(s) about some pivot point below or low in the unit. A Debris Flow is formed by loose soil, rock, organic matter, air and water and mobilizes as slurry that flows down slope. They are most commonly caused by heavy precipitation or rapid snowmelt.
Earthflows occur when slope material liquefies and runs out of the area, creating an hourglass shape. The flow is typically elongated and occurs in fine grained materials or clay bearing rocks on moderate slopes under saturated conditions. A second type of flow is a mudflow, which are typically wet materials. Creep refers to an imperceptibly slow, steady, downward movement of slope forming rock or soil. Movement occurs as a result of shear stress sufficient enough to develop deformation but too weak to form shear failure. The last type, lateral spread, usually occurs on gentle slops or flat terrain. Failures are caused by liquefaction and failure is usually triggered by ground motion such as an earthquake. An Idealized slump-earth flow showing commonly used nomenclature for labeling the parts of a landslide. (Geology.com) Landslides typically occur during periods of heavy rainfall or rapid snowmelt and can worsen the effects of flooding that accompany these events. Some landslide move slowly while other can occur rapidly, as described above, and pose a severe risk to property and life. In the United States, it is estimated that landslides cause up to $2 billion in damages and from 25 to 50 deaths annually. An additional geologic hazard that is naturally occurring but may be exacerbated by human activity is sinkhole.
Sinkholes are common where the rock below the land surface is limestone, carbonate rock, salt beds, or rocks that can naturally be dissolved by groundwater circulating through them. As the rock dissolves, spaces and caverns develop underground. Sinkholes are dramatic because the land usually stays intact for a while until the underground spaces just get too big. If there is not enough support for the land above the spaces then a sudden
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 38 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 collapse of the land surface can occur. These collapses can be small, or, as this picture shows, or they can be huge and can occur where a house or road is on top.
There are three primary types of sinkholes: Dissolution, subsidence and cover-collapse. Dissolution sinkholes occur when rainfall and surface water percolate through joints in limestone. The dissolved material is carried away from the surface and a depression gradually forms. Cavities may be formed beneath the surface. These are the most common type of sinkhole in Florida. Cover-subsidence sinkholes develop gradually when the covering sediment is permeable and contains sand. The small sediment and sand will drain into the underlying bedrock creating a vacated space allowing overlying sediment to settle. As the dissolution and infilling continue a noticeable depression will form. The slow downward erosion eventually forms a small surface depression. The final type of sinkhole is a cover-collapse sinkhole. These may develop abruptly (over a period of hours) and can cause catastrophic damages. These types of sinkholes occur where covering sediments contain a significant amount of clay which drains into a cavity in the underlying bedrock. New cavity will form in the overlying sediment and as erosion and dissolution continue the overlying cavity will migrate toward the surface. The cavity will eventually breach the ground surface creating a sudden and dramatic collapse. Sinkholes can also be created by poor land use practices resulting from ground water pumping and construction and development practices. Development increases water usage, alters drainage pathways, overloads the ground surface and redistributes soil. According to FEMA, the number of human-induced sinkholes has doubled since 1930 and insurance claims for damages as a result of sinkholes has increased 1,200 percent from 1987 to 1991, costing nearly $100 million.
4.8.2. Location and Spatial Extent
In the eastern United States, landslides are common throughout the mountainous Appalachian region and New England, predominantly from sliding of clay-rich soils. The Piedmont and Coastal Plain regions also have landslides that are commonly related to human activity such as making a road cut too steep. Areas that are generally prone to landslide hazards include previous landslide areas; the bases of steep slopes; the bases of drainage channels; and developed hillsides where leach-field septic systems are used. Figure 4.14 indicates that Onslow County uniformly resides in an area of low incidence and low susceptibility. This means that any landslide event would, at most, affect less than 1.5 percent of the total land area of the county.
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Figure 4.14 Landslide Incidences and Susceptibility Map
The susceptible areas are shown in Figure 5.13. In addition to natural processes and conditions resulting in sinkholes, areas of groundwater pumping may acceleration their formation.
In North Carolina, sinkholes are common features of the outer coastal plains where variable thicknesses of sand, silt, and clay lay over limestone rock formations. Due to these conditions, sinkholes will pose a greater threat to Onslow County than landslides do. Figure 4.15 shows susceptible areas of Onslow County created by the Castle Hayne and Riverbend limestone formations.
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Figure 4.15: Areas of Sinkhole Susceptibality
Source: NC Division of Environment and Natural Resources: Division of Water Resources
4.8.3. Historical Occurrences
There is no recorded historical evidence of significant landslide activity in Onslow County.
There is 1 recorded incident of a significant sinkhole in Onslow County in the Catherine Lake area. The property that was affected was classified as a total loss. There are multiple investigations of sinkholes throughout the county on an annual basis however; only seven other incidents have been determined to be a sinkhole of unknown origin (not related to drainage washout, collapsed culverts or rotting organic material).
4.8.4. Probability of Future Occurrences
Susceptibility to land sliding is defined by the USGS as the probable degree of response of geologic formations to natural or artificial cutting, loading of slopes, or to unusually high precipitation. Generally, it is assumed that unusually high precipitation or changes in existing conditions can initiate landslide movement in areas where rocks and soils have experienced numerous landslides in the past. Onslow County’s geography makes it least susceptible to landslides.
Susceptibility to sinkhole formation Onslow County will remain moderate due to the karst formations as described above and to continued development and industrial growth.
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4.9. Tsunami
4.9.1. Background
Tsunami is a set of ocean waves caused by any large, abrupt disturbance of the sea-surface. If the disturbance is close to the coastline, local tsunamis can demolish coastal communities within minutes. A very large disturbance can cause local devastation AND export tsunami destruction thousands of miles away. Tsunamis rank high on the scale of natural disasters. Since 1850 alone, tsunamis have been responsible for the loss of over 420,000 lives and billions of dollars of damage to coastal structures and habitats. Most of these casualties were caused by local tsunamis that occur about once per year somewhere in the world. Predicting when and where the next tsunami will strike is currently impossible. Basic tsunami formation. National Oceanic and Once the tsunami is generated, forecasting tsunami Atmospheric Administration arrival and impact is possible through modeling and measurement technologies.
Tsunamis are most commonly formed from earthquakes in marine and coastal areas. Most are produced by large, shallow earthquakes. Tsunamis are most common in the Pacific region where dense oceanic plates slide under the lighter continental plates. Underwater landslides, often associated with smaller earthquakes, are also capable of generating tsunamis as seen in 1998 in the Papua New Guinea event. Underwater volcanoes and asteroid impacts are also capable of creating tsunamis.
Tsunamis have very long wavelengths and periods and can have an average speed of 450 miles per hour. They can travel unnoticed in deep ocean waters sometimes with a wave height of only twelve inches. However, when the waves reach shallower water the wave speed slows and the wave height increases significantly. Some tsunamis can reach 100 feet in height and can cause devastation to a coastline.
An indication of an approaching tsunami would be rapid change in water levels on the coastline. The successive crests and troughs can occur from five to ninety minutes apart. Typically, the first wave is not the biggest one; therefore, it is not safe to return to the area until authorities deem it safe to return. Areas less than fifty feet above sea level and one mile inland would be at greatest risk for the impact of a tsunami. There are two types of bulletins to inform an area of the possibility of a tsunami. A Tsunami Watch Bulletin is released following an earthquake of a 6.75 or greater and a Tsunami Warning Bulletin is released when information from a tidal station indicates that the characteristics of the sea match those of a destructive tsunami. Fortunately, 75% of all warnings since 1948 have been false alarms.
According to a research paper published by the National Geophysical Data Center (Tsunamis and Tsunami-Like Waves of the Eastern United States, Lockridge, et al., 2002) since the 1600’s there have been only 40 cataloged tsunami and tsunami-like wave events that have occurred in the Eastern United States. The most notable events were the 1755 Queen Anne’s earthquake, the New Madrid earthquakes of 1811-1812, the Charleston earthquake of 1886, and the Grand Banks event of 1929. While East Coast tsunamis are rare the paper discusses two areas
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 42 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 of investigation off of the coasts of North Carolina and Virginia. Fault-like cracks in the outer continental shelf are situated in areas with large deposits of methane hydrate and pressurized water that could create unstable shelf wall leading to an underwater landslide.
4.9.2. Location and Spatial Extent
Tsunami hazard locations and extent would be similar to flood hazard areas focused slightly more primarily on the coastal areas and areas affected by tidally driven rivers and creeks.
4.9.3. Historical Occurrences
There are no historical records of tsunami events or effects in Onslow County. While these events are considered rare the potential for tsunami impacts in Eastern North Carolina does exists as evidenced by the documented occurrences along the East Coast.
4.9.4. Probability of Future Occurrences
The probability of tsunami events in Onslow County is considered to be very low. The most likely scenario, as described above, would be a landslide event on the outer continental shelf. This type of event is predicted to produce maximum wave heights of a few to several meters. Varying effects would occur from this event based on the timing of the arrival as it coincides with tidal fluctuations.
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HYDROLOGIC
4.10. Coastal and Riverine Erosion
4.10.1. Background
Erosion is a hazard defined as events in which earth is worn away, often by wind, water or ice. The process of erosion moves bits of rock, soil or sand from one place to another. Most erosion is caused by forces of moving water. This can come in the form of rain washing away soil and sand, rushing streams and rivers wearing away their banks and tides and storm surge washing away the coastal sands. Erosion is measured by its rate of change in horizontal displacement inward. Short-term riverine erosion is often secondary to heavy rainfall events, flodding and human activities such as development and removal of vegetation. Long-term riverine erosion is often a result of natural water flow forces on the banks of the river or creeks casuing slow displacement of soil, sediment and rocks. Short-term coastal erosion is often caused by hurricanes, coastal storms, and storm surge but may be exacerbated by human activities such as removal of dune and vegetative buffers and shoreline hardening and dredging. Long-term coastal erosion is a function of Long-term coastal erosion effects as seen in multi-year impacts such as normal wave action, sea level rise, Wasque, Massachusetts. The Coastlines Project sediment loss, subsidence and climate change.
Natural recover from erosion can take years to decades and can cause coastal and upland properties to be exposed to further damages in subsequent events. Erosion control is the process of reducing erosion by wind and water. Erosion control can be done by physically changing the landscape. Living shorelines are constructed by placing native plants, stone, sand, and even living organisms such as oysters along wetland coasts. These plants help anchor the soil to the area, preventing erosion. By securing the land, living shorelines establish a natural habitat. They protect coastlines from powerful storm surges as well as erosion. Physical structures such as sea walls, groins and jetties can also help mitigate coastal and riverine erosion but may also exacerbate the problem under some circumstances.
While death and injury are not typically associated with erosion issues, property damage and economic losses are.
4.10.2. Location and Spatial Extent
All of Onslow County’s coastal and riverine areas are susceptible to erosion hazards.
4.10.3. Historical Occurrences
Oceanfront shoreline change rates have been calculated using the end-point method since the first study completed in 1979. This method simply uses the earliest and most current shoreline data points where they intersect any given shore-perpendicular transect line. The distance between the two shorelines (shore-transect intersect) divided by the time between the two establishes the rate. The use of current mapping and spatial
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 44 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 analysis technology make this process repeatable and precise; ESRI's Geographic Information Systems (GIS), and USGS's Digital Shoreline Analysis System (DSAS).
The North Carolina Department of Environment and Natural Resources (NCDENR), Division of Coastal Management developed maps for Onslow County coastal zones that document the long-term average annual erosion rates. These maps were produced in 2011 and are on file at Onslow County Emergency Services. Each mapped zone and the annual erosion rate are listed as follows:
North Topsail Beach (South) – average 2 foot/year uniform North Topsail Beach (North) – average 2 foot/year, section of 2.5 foot/year, and section identified as inlet hazard area. Onslow Beach – (South) – varying averages. Extreme south section is recorded at 11 foot/year and followed by sections that progressively decrease from 10 foot/year – 2 foot per year. Onslow Beach (North) – overall average is 2 foot/year. Area of Browns Inlet identified as Inlet Hazard Area. Area just north of Browns Inlet recorded as averaging 2.5 foot/year. Browns Island (between brown Inlet and Bear Inlet) – southern section recorded as 2.5 foot/year. Northern sections approaching Bear Inlet recorded as 3 foot/year, 4.5 foot/year and 6 foot/year progressing north. Bear Island (between Bear Inlet and Bouge Inlet) – majority is recorded as 2 foot/year with the northern section recorded at 3.5 foot/year. Southern and northern ends of Bear Island are listed as Inlet Hazard Areas.
Many, if not all, of the hurricanes that have impacted Onslow County have contributed to coastal erosion issues.
4.10.4. Probability of Future Occurrences
Erosion will remain a natural, dynamic and continual process for all coastal and riverine areas of Onslow County and thus these areas have a high probability of future occurrences. While the impacts of coastal erosion can be lessened through continuous beach re-nourishment programs, it is likely that the impacts will increase in severity over time due to the anticipated slow-onset, long-term effects of climate change and sea-level rise. Figure 4.16 shows the probabilities of coastal change along the Onslow County coastline.
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Figure 4.16: Coastal Change Probabilities
Source: United States Geological Society, St. Petersburg Coastal and Marine Science Center
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4.11. Dam and Levee Failure
4.11.1. Background
Dam and Levee failures are a result of aging infrastructure. The primary concerns of these types of hazards stems from their direct impacts on citizens. Growing populations in areas around and downstream of dams and levees has increased the emphasis on safety, operation, maintenance and risk.
While there are approximately 80,000 dams in the United States, owned by private individual, state and local authorities, public utilities and federal agencies. North Carolina currently has an inventory of over 5,000 dams. Dams provide numerous benefits to include: providing drinking water, navigation, agricultural irrigation, hydroelectric power, recreational and flood mitigation.
Should a dam or levee fail, the stored energy of the ater would create flash flood events for areas downstream that would result in property damage and possible loss of life. Failures of dams and levees have the potential to place large numbers of people and large areas of property in harm’s way.
In North Carolina the regulating agency for dams and levees is the North Carolina Department of Environment and Natural Resources; Division of Energy, Mineral and Land Resources. The division classifies dams for hazard potential and has developed a hazard classification system as outlined in Table 4.13.
Table 4.13: North Carolina Dam Hazard Classifications Hazard Description Qualitative Guidelines Classification Interruption of road service (low volume roads) Less than 25 vehicles a day Low Economic Damage Less than $30,000 Interruption of road service (low volume roads) 25- 250 vehicles a day Intermediate Economic Damage $30,000-$200,000 Loss of Human Life Probable loss of 1 or more lives Interruption of road service (low volume roads) Greater than 250 vehicles a day High Economic Damage More than $200,00 Loss of Human Life Probable loss of 1 or more lives Source: North Carolina Department of Environment and Natural Resources, Division of Energy, Mineral and Land Resources
4.11.2. Location and Spatial Extent
Onslow County currently has seven earthen dams listed in the North Carolina Dam Inventory, produced by the NCDENR, Division of Energy, Mineral and Land Resources. One is federally owned and on Camp Lejeune proper. There are four listed as local government and serve as wastewater treatment lagoons. There are three listed as private, with one serving as a waste/treatment lagoon and two serving as recreational. The list of dams and their hazard classification is given below:
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Table 4.14: Onslow County Dam Inventory Hazard Conditional Surface Max Capacity Type of Dam Name Potential Assessment Area (Acres/Foot) Owner Yow-Williams Dam Low Satisfactory 176 Private Henderson Lake Dam (DoD) Low Not Rated 90 Federal Kenan Pond Dam Low Satisfactory Private Jacksonville Wastewater Lagoon High Satisfactory 500 15 Local Govt. Jacksonville LTS – South Storage Lagoon High Satisfactory Local Govt. North Topsail Water & Sewer Lagoon (Pluris) High Satisfactory 10 180 Local Govt. Oceanview Farms (Coharie Farms) Low Satisfactory 8 90 Private Elizabeth Lake (Dewitt Pond, Preston Pond) REMOVED Not Rated N/A N/A N/A Source: North Carolina Department of Environment and Natural Resources, Division of Energy, Mineral and Land Resources
4.11.3. Historical Occurrences
There are no recorded events of dam/levee failure in Onslow County. The Elizabeth Lake dam is listed as “breeched” however, this was an intentional breech in an effort to drain and remove the dam. No damages occurred as a result of this incident.
4.11.4. Probability of Future Occurrences
There is a low probability of dam or levee failure in Onslow County. However, as indicated in Table 4.14 three dams exist that have a potential to create catastrophic damages to property and loss of life.
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4.12. Flooding
4.12.1. Background
Flooding is a coast to coast threat in the United States and its territories in all months of the year. It is the most frequent and costly hazard with approximately 75 percent of all presidential disaster declarations resulting from natural events where flooding was the major component. In most years it causes more damage in the United States than any other severe weather related event – an average of $5.3 billion a year for the 30-year period, 1975-2004. During this same period, an annual average of 93 people lost their lives due to flooding.
Flooding typically occurs when prolonged rain falls over several days, when intense rain falls over a short period of time, or when an ice or debris jam causes a river or stream to overflow onto the surrounding area. Flooding can also be caused by the failures of water control structures such as dams and levees. The most common cause of flooding is water due to rain and/or snowmelt that accumulates faster than soils can absorb it or rivers can carry it away. The severity of flood events is typically determined by a combination of river basin topography and physiography, precipitation and weather patterns, recent soil moisture condition, and the degree of vegetation and/or cleared/impervious surfaces.
There are two primary categories of flood types: general and flash. General flooding is typically a long term event that may last for several days. General flooding can be further divided into three categories. 1) Riverine flooding occurs when river levels rise and overflow their banks or the edges of their main channels. River flooding can be caused by heavy rainfall, dam failures, rapid snowmelt and ice jams. 2) Coastal flooding is typically a result of storm surge, wind driven waves, and heavy rainfall produced by hurricanes or other coastal storms. 3) Urban flooding results because urbanization increases the magnitude and frequency of floods by increasing impermeable surfaces, increasing the speed of drainage collection, reducing the carrying capacity of the land, and occasionally overwhelming sewer systems.
Flash Floods, the second general type of flood, can be caused by slow moving thunderstorms and dam or levee failures. These types of events are rapid and usually occur within six hours of the immediate cause and result in a very rapid rise of water over ow-lying areas. Steep, hilly or mountainous terrain are at greater risk of flash flooding as are urban areas due to the large expanses of concrete and asphalt surface that do not allow for adequate water absorption.
Periodic flooding of lands adjacent to non-tidal rivers and streams (area known as a floodplain) is a natural and inevitable occurrence and can be expected to take place within regular recurrence intervals. The recurrence interval of a flood is defined as the average time, in years, expected between a flood event of a particular magnitude and an equal or larger flood. Periodic flooding of lands adjacent to non-tidal rivers and streams is a natural and inevitable occurrence. Floodplains are defined by the frequency of a flood that is large enough to cover it. For example, a reference to a 100 year floodplain means that a 100 year flood will cover that specified area. To help better define the
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 49 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 floodplain the National Flood Insurance Program (NFIP) developed a common standard of baseline probability. The “base” flood is the 1% (1 out of 100) annual chance of a flood occurring during any given year. The base flood is thus refered to, informally, as the 100 year flood. Often misunderstood, the term 100 year flood does not mean that a flood will only occur once in a 100 year span but instead means that on any given year an area has a 1% chance of a flood occurring. Thus an area could see a 100 year flood twice in the same year, two years in a row or not at all over a 200 year span.
The NFIP has developed a mapping system to identify flood plone area in an effort to help communities understand their risk. Three main categories of risk areas are defined: 1) High-Risk Area (special flood hazard area or SFHA) where there is a 1 in 4 chance of flooding during a 30 year period. These are typically indicated on a flood map zones with a letter A or V. 2) Moderate-To-Low Risk Areas (non-special flood hazard area or NSFA) are areas that are at risk of being flooded but not completely removed. They will typically be identified on flood map zones with letter B, C or x (or a shaded x). 3) Undetermined-Risk Areas are areas where no flood- hazard analysis has been conducted but a flood risk may still exist. These areas will be labeled with a letter D on flood maps. Table 4.15 provides a full breakdown of the flood zones found on typical flood zone maps.
Table 4.15: NFIP Flood Insurance Rate Map Designations Zone Designation A The flood insurance rate zone that corresponds to the 100-year floodplains that is determined in the Flood Insurance Study by approximate methods. Because detailed hydraulic analyses are not performed for such areas, no Base Flood Elevations or depths are shown within this zone. Mandatory flood insurance purchase requirements apply. A99 The flood insurance rate zone that corresponds to areas of the 100-year floodplains that will be protected by a Federal flood protection system where construction has reached specified statutory milestones. No Base Flood Elevations or depths are shown within this zone. Mandatory flood insurance purchase requirements apply. AE and The flood insurance rate zone that corresponds to the 100-year floodplains that is determined in the Flood A1-A30 Insurance Study by detailed methods. In most instances, Base Flood Elevations derived from the detailed hydraulic analyses are shown at selected intervals within this zone. Mandatory flood insurance purchase requirements apply. AEFW 100-year floodway; The floodway is an area that includes the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water-surface elevation by more than a designated height. AH The flood insurance rate zone that corresponds to the areas of the 100-year shallow flooding with a constant water-surface elevation (usually areas of ponding) where average depths are between 1 and 3 feet. The Base Flood Elevations derived from the detailed hydraulic analyses are shown at selected intervals within this zone. Mandatory flood insurance purchase requirements apply. AO The flood insurance rate zone that corresponds to the areas of 100-year shallow flooding (usually sheet flow on sloping terrain) where average depths are between 1 and 3 feet. The depth should be averaged along the cross section and then along the direction of flow to determine the extent of the zone. Average flood depths derived from the detailed hydraulic analyses are shown within this zone. In addition, alluvial fan flood hazards are shown as Zone AO on the Flood Insurance Rate Map. Mandatory flood insurance purchase requirements apply. AR The flood insurance rate zone that results from the decertification of a previously accepted flood protection system that is being restored to provide protection from the 100-year or greater flood event. D Designation on National Flood Insurance Program maps used for areas where there are possible, but undetermined, flood hazards. In areas designated as Zone D, no analysis of flood hazards has been conducted. Mandatory flood insurance purchase requirements do not apply, but coverage is available. The flood insurance rates for properties in Zone D are commensurate with the uncertainty of the flood risk.
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V The flood insurance rate zone that corresponds to the 100-year coastal floodplains that have additional hazards associated with storm waves. Because approximate hydraulic analyses are performed for such areas, no Base Flood Elevations are shown within this zone. Mandatory flood insurance purchase requirements apply. VE The flood insurance rate zone that corresponds to the 100-year coastal floodplains that have additional hazards associated with storm waves. Base Flood Elevations derived from the detailed hydraulic analyses are shown at selected intervals within this zone. Mandatory flood insurance purchase requirements apply. B,C,X Zones B, C, and X are the flood insurance rate zones that correspond to areas outside the 100-year floodplains, (shaded areas of 100-year sheet flow flooding where average depths are less than 1 foot, areas of 100-year stream X) flooding where the contributing drainage area is less than 1 square mile, or areas protected from the 100-year flood by levees. No Base Flood Elevations or depths are shown within this zone. Source: Federal Emergency Management Agency, National Flood Insurance Program
4.12.2. Location and Spatial Extent
Many areas in Onslow County are susceptible to riverine, urban (storm water), and coastal flooding. It is estimated that almost 21 % (161 square miles) of Onslow County are located in one of the Special Flood Hazard Areas. Figure 4.17 illustrates the flood zone classifications within Onslow County based on current Flood Insurance Rate Maps. This map includes zones A, AE, AEFW, Shaded x and VE as described above. It is important to note that while FEMA digital flood insurance rate maps are recognized as the best available data for planning purposes; it does not always reflect the most accurate and up-to-date flood risk. Flooding and flood-related losses often do occur outside of delineated special flood hazard areas.
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Figure 4.17: Special Flood Hazard Areas in Onslow County
Sources: Federal Emergency Management Agency, National Flood Insurance Program, Onslow County GIS
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4.12.3. Historical Occurrences
Onslow County has areas that are prone to generalized flooding. These areas include:
Bachelor's Delight Swamp/ Tributary Blue Creek, Brinson Creek Brynn Mar Cowford Branch, Half Moon Creek Half Moon Creek Tributary Jenkins Swamp Mill Swamp Mott Creek New River New River Tributary North Branch at Lauradale Subdivision Northeast Creek Wolf Swamp Rocky Run Scales Creek South Branch at Lauradale Subdivision
The National Climatic Data Center lists 28 reported flood events throughout Onslow County since 1996. This list also includes two documented events that are not reported by the NCDC; one in 1994 and one in 1995. Both are documented in local histories.
Table 4.16: Historical Flood Events in Onslow County Death / Property
Location Date Type Crop Damage
Injury Damage Onslow County 12/23/1994 Flooding 0/0 0.00K 0.00K Onslow County 09/08/1995 Coastal Flooding 0/0 500.00K 0.00K Richlands 07/23/1996 Flash Flood 0/0 0.00K 0.00K Richlands 09/11/1996 Flash Flood 0/0 0.00K 0.00K Jacksonville 10/08/1996 Flash Flood 0/0 80.00K 0.00K Jacksonville 05/17/1998 Flash Flood 0/0 0.00K 0.00K Countywide 09/15/1999 Flash Flood 0/0 0.00K 0.00K Countywide 09/16/1999 Flash Flood 0/0 0.00K 0.00K Countywide 10/17/1999 Flash Flood 0/0 0.00K 0.00K Camp Lejeune 08/04/2000 Flash Flood 0/0 100.00K 0.00K Sneads Ferry 08/04/2000 Flash Flood 0/0 0.00K 0.00K Countywide 09/18/2000 Flash Flood 0/0 1.000M 0.00K Jacksonville 07/31/2002 Flash Flood 0/0 0.00K 0.00K Countywide 05/23/2003 Flash Flood 0/0 0.00K 0.00K
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Richlands 07/02/2003 Flash Flood 0/0 0.00K 0.00K Jacksonville 07/11/2004 Flash Flood 0/0 0.00K 0.00K Countywide 08/14/2004 Flash Flood 0/0 0.00K 0.00K Countywide 10/07/2005 Flood 0/0 0.00K 0.00K Countywide 06/28/2006 Flood 0/0 50.00K 0.00K Richlands 06/30/2006 Flash Flood 0/0 0.00K 0.00K Bell Fork 04/15/2007 Flood 0/0 0.00K 0.00K Bell Fork 08/06/2009 Flood 0/0 0.00K 0.00K Bell Fork 08/12/2009 Flood 0/0 0.00K 0.00K Folkstone 09/07/2009 Flood 0/0 0.00K 0.00K Swansboro 11/12/2009 Flood 0/0 0.00K 0.00K Bell Fork 06/25/2010 Flood 0/0 0.00K 0.00K Jacksonville Ellis Airport 09/29/2010 Flood 0/0 0.00K 0.00K Catherine Lake 09/30/2010 Flash Flood 0/0 1.000M 6.000M Countywide 06/29/2011 Flood 0/0 0.00K 0.00K Half Moon 08/06/2011 Flood 0/0 0.00K 0.00K Totals: 0/0 2.230M 6.000M
Source: NOAA, National Climatic Data Center
4.12.4. Historical Summary of Insured Flood Losses
According to the Federal Emergency Management Agency flood insurance policy records, as of May 2014, there have been more than 3,245 flood losses reported in Onslow County through the National Flood Insurance Program since 1978. These losses have totaled over $40 million in claims payments. Table 4.17 lists flood losses and payments by jurisdiction. These losses include both inland and coastal flood events. It should be noted that these numbers include only those losses to structures that were insured, reported and paid out through NFIP policies. It is highly probable that additional flood losses have occurred in Onslow County that were uninsured or not reported.
Table 4.17: NFIP Claims for Onslow County (1978-2014) Total Community Name Total Payments Losses Holly Ridge 1 $7,231.05 Jacksonville 144 $1,784,230.08 NTB 1,214 $14,571,476.53 Onslow County (unincorporated areas) 1,787 $22,070,474.74 Richlands 1 $ 6,685.92 Swansboro 98 $2,165,835.84 3245 $40,605,934.16 Source: Federal Emergency Management Agency
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4.12.5. Repetitive Loss Properties
FEMA defines a repetitive loss (RL) property as any insurable building for which two or more claims of more than $1,000 were paid by the NFIP within any rolling 10 year period since 1978. A repetitive loss property may or may not be currently insured by the NFIP. Severe Repetitive Losses (SRL) are classified as any property that has at least four claims payments, each over $5,000 and a cumulative amount that exceeds $20,000 or any property with at least two separate claims payments in which the cumulative amount of the building portion exceeds the market value of the building.
According to the North Carolina Emergency Management, Onslow County has 446 repetitive loss properties and 29 severe repetitive loss properties. Of the repetitive loss properties, 20 are in the City of Jacksonville, 254 in the Town of North Topsail Beach, 21 in the Town of Swansboro and 151 in the unincorporated areas of the county. Of the severe repetitive loss properties 20 are in North Topsail Beach, 2 are in Swansboro, and 4 are in the unincorporated areas of Onslow County. Total losses paid for all of the RL’s and SRL’s is approximately $25 million.
4.12.6. Probability of Future Occurrences
Flood events will remain frequent events in Onslow County and the probability of future occurances is high and almost certain. The probability based on magnitude and best data is illustrated in Figure 4.15 above. Further, as describe in other hazard profiles riverine and coastal flooding are closely associated with tropical storms, hurricanes and other coastal storms.
It should be discussed that data supporting sea level rise will most probably increase the intensity and probability of future tidal flooding events. As is also discussed in Section 4.10 erosion will also contribute to the increased magnitude of flood events.
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4.13. Storm Surge
4.13.1. Background
Along the coast, storm surge is often the greatest threat to life and property from a hurricane. In the past, large death tolls have resulted from the rise of the ocean associated with many of the major hurricanes that have made landfall. Hurricane Katrina (2005) is a prime example of the damage and devastation that can be caused by surge. At least 1500 persons lost their lives during Katrina and many of those deaths occurred directly, or indirectly, as a result of storm surge.
Storm surge is an abnormal rise in water generated by a storm. This is over and above the predicted astronomical tide. Storm surge is sometimes confused with storm tide. Storm tide is defined as the water level rise due to the combination of storm surge and astronomical tide (thus it is an accumulative level). Storm surge can casue significant flooding particularly when it occurs in relation to normal high tide. Figure 4.18 provides a visual representation of storm sruge and storm tide.
Figure 4.18: Storm Surge vs. Storm Tide
Source: NOAA: National Hurricane Center
Storm surge is produced when water is pushed toward the shore by the forces of winds moving cyclonically around a storm. The impacts of low barometric pressures are minimal on surge when compared to the wind driven forces. The maximal storm surge for any given area is complex as it can be affected by slight changes in strom intensity, forward speed, radius of maximum winds, angle of approach, central pressures, and the shape and characteristics of coastline features. A shallow slope has the potential for a great more intense storm surge to develop than sharp steep slope. Storm surge will inundate coastal floodplains by dune overwash, tidal elevation rise in inland bays and backwater flooding through coastal river mouths.
The storm surge arrives ahead of the storm center’s actual landfall and the more intense the storm is, the sooner the surge arrives. Water rise can be very rapid, posing a serious threat to those who have not yet evacuated flood‐prone areas. he surge is always highest in the right‐front quadrant of the direction in which the storm is moving. As the storm approaches shore, the greatest storm surge will be to the north of the low‐pressure system or hurricane eye. Such a surge of high water topped by driven by hurricane force winds can be devastating to coastal regions, causing severe beach erosion and property damage along the immediate shoreline.
4.13.2. Location of Spatial Extent
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Storm surges can be extremely dangerous to coastal communtieis in North Carolina, and the coastline of Onslow County. Storm surge can present a greater threat to a community during a hurricane and coastal storm than the winds.
Figure 4.19 shows hurricane inundations expected with each category of hurricane across Onslow County. The map was produced by FEMA in coordination with NOAA and the US Army Corps of Engineers (USACE). The map represents the potential for flooding from hurricanes based on storm surge heights calculated by the National Weather Service’s SLOSH (Sea, Lake, and Overland Surge from Hurricanes) Model. SLOSH storm surge elevations represent the worst case combinations of direction, forward speed, landfall, and astronomical tide. The maps do not include wave heights that may accompany storm surge.
Figure 4.19: Storm Surge Inundation in Onslow County
Source: FEMA, NOAA, USACE (HURREVAC)
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As Figure 4.19 shows areas closest to coastal areas are at high risk of storm surge inundation in addition most riverine floodplains along most rivers. Areas not located immediately along the coast or major rivers may not be directly impacted except in extreme storm events, they may experience flooding caused by storm surge and extremely high tides.
4.13.3. Historical Occurrences
NOAA and the National Climatic Data Center (NCDC) started recorded storm surge events in 1996. Prior to that storm surge events were not individually categorized apart from hurricane and coastal storm events. According to the NCDC there has been one recorded event of storm surge as shown in Table 4.17.
Table 4.17: Historical Storm Surge Events in Onslow County Death Property Description
Location Date Type Mag /Injury Damage Hurricane Irene made landfall as a large category 1 hurricane on the Saffir/Simpson Hurricane Wind Scale during the morning of the 27th. Due to the large size of the hurricane strong damaging winds, major storm surge, and flooding rains were experienced across much of eastern North Carolina. Storm surge damages were estimated at 420 million dollars. Across Onslow Storm county...winds of 50 to 60 mph resulted in numerous ONSLOW 08/26/2011 0/0 8.000M Surge/tide trees and power lines down with minor structural damage and extensive power outages. The Highest storm surge was 5.5 feet at North Topsail beach. Other locations receiving a 2 to 3 foot storm surge were Sneads Ferry and Swansboro. Storm total rainfall of 7 to 12 inches resulted in Flooding of streets and other low lying areas. One man died from a Heart attack while boarding up prior to the hurricane. Totals: 0/0 8.000M
Source: National Climatic Data Center
4.13.4. Probability of Future Occurrences
It is likely that Onslow County will continue to experience storm surge associated with large tropical storms, hurricanes, and other coastal storms. As previously discussed, anticipated sea level rise will increase the probability and intensity of future storms. This may cause not only stronger intensity events but may also contribute to the loss of coastal wetlands and erosion of the beaches that serve as natural buffers against the storm surge.
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OTHER
4.14. Wildfire
4.14.1. Background
A wildfire is an uncontrolled burning of grasslands, brush, or woodlands. The potential for wildfire depends upon surface fuel characteristics, recent climate conditions, current meteorological conditions and fire behavior. Hot, dry summers and dry vegetation increase susceptibility to fire in the fall, a particularly dangerous time of year for wildfire. Wildfires are part of the natural management of forest ecosystems, but may also be caused by human factors. Nationally, over 75,000 wildfires occur each year. Around 90 percent of forest fires are started by negligent human behavior such as smoking in wooded areas or improperly extinguishing campfires. The second most common cause for wildfire is lightning. Fireseason in the southeastern United States runs from March through May.
There are three general patterns of fire spread: 1) Ground Fires – which burn organic matter in the soil beneath surface litter and aree sustained by glowing combustion; 2) Surface Fires – which spread with a flaming front and burn leaf litter, fallen branches and other fuels located at ground level; and 3) Crown Fires – which burn through the top layer of foliage on a tree, known as the canopy or crown fires. Crown fires, the most intense type of fire and often the most difficult to contain, need strong winds, steep slopes and a heavy fuel load to continue burning.
The potential for a major fire hazard depends on the characteristics of the fuel, the climate (local weather conditions), outdoor activities, debris burning and construction, and the degree of public cooperation with fire prevention measures. Understanding the fuel characteristic is important because a fuel’s composition, including moisture level, chemical makeup and density, determines its degree of flammability. Moisture level is the most important consideration. Live trees usually contain a great deal of moisture while dead logs contain very little. The moisture content and distribution of these fuels define how quickly a fire can spread and how intense or hot a fire may become. High moisture content will slow the burning process since heat from the fire must first eliminate moisture. In addition to moisture, a fuel’s chemical makeup determines how readily it will burn. Some plants, shrubs and Source: US Department of Interior, trees contain oils or resins that promote combustion, causing them to National Park Service burn more easily, quickly or intensely than those without such oils. Soil types also must be considered because fire affects the environment above and below the surface. Soil moisture content, the amount of organic matter present and the duration of the fire determine to what extent soil will be affected by fire.
Weather conditions such as wind, temperature and humidity also contribute to fire behavior. Wind is one of the most important factors because it can bring a fresh supply of oxygen to the fire as well as push the fire toward a new fuel source. Temperature of fuels is determined by the ambient temperature since fuels attain their heat by absorbing surrounding solar radiation. Humidity, the amount of water vapor in the air, affects the moisture level
SECTION 4: HAZARD IDENTIFICATION & ANALYSIS 59 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 of a fuel. At low humidity levels, fuels become dry and, therefore, catch fire more easily and burn more quickly than when humidity levels are high.
The wildland urban interface (WUI) is the area where structures and other human development meet or intermingle with undeveloped wildland, forest or vegetative fuels. North Carolina has more WUI acres than any other state in the country and our growth increases this acreage every year. The interface creates great challenges for fire managers as nearly every fire or its associated smoke may impact homes, roads, farms or other development. Further, the increasing demand for outdoor recreation places more people in wildlands during holidays, weekends and vacation periods. Unfortunately, wildland residents and visitors are rarely educated or prepared for wildfire events that can sweep through the brush and timber and destroy property within minutes.
Wildfires can result in economic losses as well. Besides disruptions to business in or near the fire areas, outdoor recreational business, logging and paper product companies, and tourism based companies can all be impacted by wildfires. These impacts, if persistent, can result in economic losses that result in lost jobs. State and local governments can impose fire safety regulations on home sites, new developments, and industry to help with wildfire hazards. Communities can also adopt Firewise principles to help mitigate and reduce their risk. Hazard reduction can include land treatment measures such as fire access roads, water storage, safety zones, buffers, firebreaks, fuel breaks and fuel management. Fuel management, along with prescribed burning programs and cooperative land management planning can all be utilized to help reduce fire hazards.
4.14.2. Location and Spatial Extent
All areas of Onslow County are susceptible to wildfire and the wildland-urban interface is an area of concern with the continued residential growth. Further, drought conditions could exacerbate the risk of wildfire events in Onslow County.
4.14.3. Historical Occurrences
Table 4.18 shows a list of historical fire occurrences in Onslow County from 1993-2013. The list is a total number of occurrences throughout the County by year of incident along with a total number of acres burned. If specific locations are known they are also included. Figure 4.20 shows the fire occurrence areas (FOA) based on data from the Southern Wildfire Risk Assessment. Fire Occurrence is derived by modeling historic wildfire ignition locations to create an average ignition rate map. The ignition rate is measured in the number of fires per year per 1,000 acres. Figure 4.21 is the wildland-urban interface risk index which reflects housing density in those specific areas where structures meet or intermix with wildland fuels.
Table 4.18: Historical Wildfire Occurrences in Onslow County (1993-2013) Date Locations # Acres # Fires Occured 1993 Countywide 405 102 1994 Countywide 743 120 1995 Countywide 430 84 1996 Countywide 312 59 1997 Countywide 379 117 1998 Countywide 172 65 1999 Countywide 430 97 2000 Countywide 308 82
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2001 Countywide 322 132 2002 Countywide 239 89 2003 Countywide 144 49 2004 Countywide 210 91 2005 Piney Green / Crown Point 334 92 2006 Sandridge / Crown Pint/ Haw Branch 1275 87 2007 Piney Green / Crown Point/ Haw Branch / Queens Haven 319 116 2008 Catherine Lake /Blue Creek / Angola / Gurganus Rd. 452 77 2009 Countywide 100 77 2010 Countywide 201 91 2011 Countywide 1671 152 06/2011 GSR - 8 30k+ 1 06/2011 Holly Shelter 60k+ 1 2012 Countywide 72.5 52 2013 Countywide 562.6 42 Source: North Carolina Forest Service
According to the North Carolina Forest Service data this results in an average of approximately 432 acres per year and an average of 89 fires annually in Onslow County.
Figure 4.20: Fire Occurrence Areas in Onslow County
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Figure 4.21: Wildland Urban Interface Risk Index in Onslow County
Source: Southern Wildfire Risk Assessment (SWRA)
4.14.4. Probability of Future Occurrences
There is a moderate probability of future wildfire events in Onslow County, this may increase during drought cycles and abnormally dry conditions.
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4.15. Conclusions on Hazard Identification and Analysis
The hazard profiles presented in this section were developed using best available data from reputable sources. Government data was predominantly utilized and outside information was only utilized if no government data existed for the specific information. This profile should severe as a qualitative assessment as recommended be FEMA in their “How-to” guidance document titled Understanding Your Risks: Identifying Hazards and Estimating Losses (Publication 386-2). This profile relies heavily on historical and anecdotal data, stakeholder input, government research datasets, and professional and experienced judgment regarding observed and/or anticipated hazards. Other relevant plans, studies and technical reports were also consulted.
The following sources were among those used to develop the identification and analysis for this section:
NC Department of Public Safety: Division of Emergency Management: Hazard Mitigation Planning (https://www.nccrimecontrol.org) Federal Emergency Management Agency (www.fema.gov) National Weather Service (www.weather.gov) National Oceanic and Atmospheric Administration: National Climatic Data Center (www.ncdc.noaa.gov) Southern Group of State Foresters: Wildfire Risk Assessment Portal (http://www.southernwildfirerisk.com/ ) National Integrated Drought Information Center (www.drought.gov) United States Geological Society (www.usgs.gov) United States Army Corps of Engineers: National Inventory of Dams (http://geo.usace.army.mil/pgis/f?p=397:1:0) North Carolina Department of Environment and Natural Resources (http://portal.ncdenr.org/web/guest) National Oceanic and Atmospheric Administration: National Hurricane Center (www.nhc.noaa.gov) National Oceanic and Atmospheric Administration: National Severe Storms Laboratory (www.nssl.noaa.gov)
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5. VULNERABILITY ASSESMENT
Vulnerability to a natural hazard measures the extent to which people are expected to experience physical harm and the likelihood of property damage. It is important to know where and to what extent the community is susceptible to the impacts of natural hazards. The current level of development and infrastructure generates a set of conditions, resulting in every area having some degree of vulnerability to natural hazards. That degree of vulnerability will change in the future as an area experiences an increase or decrease in development and whether the community implements or ignores hazard mitigation. Therefore, we can speak of both present vulnerability and future vulnerability. Currently most available historic data is only countywide and will be used for both the County’s and municipal planning jurisdictions.
The vulnerability section is designed to build upon the information provided in Section 4: Hazard Identification and Analysis by identifying community ELEMENTS B3 & B444 CFR Part assets, potentially at-risk populations and development trends in Onslow 201.6(c)(2)(ii): County and then assesses the potential impact and amount of damages that The risk assessment shall could be caused by each of the identified hazards previously addressed. The include a description of the jurisdictions vulnerability to the primary objective of a vulnerability assessment is to help better understand hazard described in paragraph the unique risks to identified hazards and better prioritize those risks to (c)(2)(i) f this section. The develop sound mitigation strategies and policy development. To maintain description shall include an consistency with previous sections the hazards will be addressed in the overall summary of each following order: hazard and its impact on the community. All plans approved Atmospheric after October 1, 2008, must also address NFIP insured o 5.3 Drought and Heat Wave structures that have been o 5.4 Severe Thunderstorm and Hail repetitively damaged by floods. o 5.5 Hurricane and Coastal Storm (includes Nor’easter) The plan should describe o 5.6 Tornado vulnerability in terms of: o 5.7 Winter Storm (A) The types and numbers of existing and future buildings, infrastructure, and critical Geologic facilities located in the o 5.8 Earthquake identified hazards; o 5.9 Landslide and Sinkhole (B) An estimate of the potential o 5.10 Tsunami losses to vulnerable structures identified in paragraph (c)(2)(ii)(A) of this section and a Hydrologic description of the methodology o 5.11 Coastal and Riverrine Erosion used to prepare the estimate; o 5.12 Dam and Levee Failure (C) Providing a general description of land uses and o 5.13 Flooding development trends within the o 5.14 Storm Surge community so that mitigation options can be considered in Other future land use decisions.
o 5.15 Wildfire
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To complete the vulnerability assessment multiple sources were consulted for best available data including, federal, state, and local agencies. Additional work will be done on an ongoing basis to continually enhance, expand and improve the accuracy of the initial results. The changes will be incorporated into future plans on an as needed basis. This assessment was conducted utilizing best available data to develop an approximation of risk. Estimates should be used to understand the relative hazard risks and potential losses that may occur. It should be noted that uncertainties are inherent in any loss estimation methodology, arising in part from incomplete scientific data and knowledge in reference to a specific hazard and their effects on the built environment and form approximations that are necessary to build a comprehensive analysis.
5.1. Methodology
The vulnerability assessment was completed utilizing three distinct methodologies. The first is a geographic information system (GIS) based analysis. The second utilizes statistical risk assessment methodology. The third is a qualitative based approach. Each approach provides estimates for the potential impact of hazards using a common, systematic framework for evaluation, including historical occurrence provided in Section 4. The methodologies are briefly described and introduced here and are further illustrated throughout this section. For each hazard addressed, the vulnerability is summarized in part by an annualized loss estimate specific to that hazard along with a Priority Risk Index (PRI) value described below.
A GIS based analysis was conducted for the following hazard groups:
Hurricane and Coastal Storm (including Nor’easter) Earthquake Landslide and Sinkhole Coastal and Riverrine Erosion Dam and Levee Failure Flooding Storm Surge Wildfire
A statistical risk assessment approach was used to analyze the remaining hazard groups:
Drought and Heat Wave Severe Thunderstorm and Hail Tornado Winter Storm Tsunami
5.1.1. GIS-Based Analysis
GIS based analysis is based on digital data that is collected from local, regional, state and national sources. The Onslow County Geographical Information System (GIS) Division utilized the latest version of ESRI ArcGIS to help assess hazard vulnerability. Utilizing data layers programmed into the ArcGIS program hazard
SECTION 5: VULNERABILITY ASSESSMENT 2 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 vulnerability can be quantified by estimating the assessed building value for parcels and/or buildings determined to be located in identified hazard areas. FEMA’s HAZUS-MH software was also utilized to model hurricane winds, riverrine flood, and estimate potential losses for these hazards. The result in this analysis is an estimate of the number of people, buildings and critical facilities, as well as a value of the buildings, determined to be at a potential risk for those hazards with a delineable geographic boundary.
HAZUS-MH
HAZUS-MH is a nationally applicable standardized methodology that contains models for estimating potential losses from earthquakes, floods and hurricanes. HAZUS-MH uses Geographic Information Systems (GIS) technology to estimate physical, economic and social impacts of disasters. It graphically illustrates the limits of identified high-risk locations due to earthquake, hurricane and floods. Users can then visualize the spatial relationships between populations and other more permanently fixed geographic assets or resources for the specific hazard being modeled, a crucial function in the pre-disaster planning process. HAZUS-MH uses a statistical approach and mathematical modeling of risk to predict a hazards frequency of occurrence and estimated impacts based on recorded historical damage information. The HAZUS-MH risk methodology is described as being parametric, in that distinct hazard and inventory parameters (such as wind speed and building type) were modeled to determine the impact (damages and losses) on the built environment. Figure 5.1 shows a conceptual model of HAZUS-MH methodology.
Figure 5.1: Conceptual Model of HAZUS-MH Methodology
5.1.2. Statistical Risk Assessment Methodology
For those hazards that occur outside the scope of HAZUS and GIS based approaches a statistical risk assessment methodology was utilized. These hazards include drought and heat wave, severe thunderstorm and
SECTION 5: VULNERABILITY ASSESSMENT 3 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 hail, tornado, tsunami and winter storm. Because these hazards do not have clearly defined geographical boundaries they cannot be assessed utilizing spatial analysis through GIS systems. This method follows the same principles as HAZUS. First, historical data is compiled for each hazard to relate occurrence patterns (frequency, intensity, damage, etc...) with existing hazard models. When possible, qualitative hazard loss estimates are compared with historical damage data as recorded through reliable sources (local documentation, National Climatic Data Center, etc…) and average annual loss estimates are identified. Hazards that were analyzed utilizing HAZUS were run through a probabilistic “worst case scenario” result to show the maximum potential extent of damages. It should be noted that smaller events would thus create lower losses that are estimated here.
5.1.3. Qualitative Methodology
A qualitative assessment relies less on technology and more on historical and anecdotal data, community input and professional judgment regarding expected hazard impacts. The qualitative method chosen for the Onslow County Hazard Mitigation Plan is the Priority Risk Index (PRI). The purpose of the PRI is to categorize and prioritize all potential hazards as high, moderate or low risk. The PRI is assessed on all hazards but is used to assist with hazards that have no available GIS data or relevant information to perform a quantitative analysis.
The PRI results in numerical values that allow all identified hazards to be ranked against one another on a standard scale, the higher the risk, the higher the PRI value. PRI values are obtained by assigning varying degrees of risk to each hazard across five different categories: probability, impact, spatial extent, warning time and duration. Each category has varying degrees of risk and each degree of risk is assigned a numerical value (1 to 4). Each category is then weighted against the other categories. Table 5.1 lists the categories, degrees of risk, and weighted values. The PRI value is then calculated by multiplying the weighting factor against the category value for each hazard and summing each categories value together. The highest PRI values that can be assigned are 4.0 based on the equation (1 being the lowest risk and 4 being the highest risk). The equation is written:
PRI VALUE = [(PROBABILITY x .30) + (IMPACT x .30) + (SPATIAL EXTENT x .20) + (WARNING TIME x .10) + (DURATION x .10)]
Estimated maximum severity levels (impact) such as magnitude and extent were classified according to scientific scales such as the Saffir-Simpson scale for hurricanes, Enhanced Fujita scale for tornados, Modified Mercalli Intensity for earthquakes and Palmer Drought Severity Index for drought. For those hazards with no scientifically approved scale, only qualitative descriptions of severity are provided based on the hazard identification in Section 4.
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Table 5.1: Priority Risk Index Summary Degree of Risk Assigned PRI Index Weighting Category Level Criteria Value Factor
Unlikely Less than 1% annual probability 1
Possible Between 1 and 100% probability 2 Probability 30% Likely Between 10 and 100% probability 3
Highly Likely 100% annual probability 4
Very few injuries, if any. Only minor property damage and minimal Minor disruption on quality of life. Temporary shutdown of critical 1 facilities. Minor injuries only. More than 10% of property in affected area Limited damaged or destroyed. Complete shutdown of critical facilities for 2 more than one day. Impact 30% Multiple deaths/injuries possible. More than 25% of property in Critical affected area damaged or destroyed. Complete shutdown of critical 3 facilities for more than one week. High number of deaths/injuries possible. More than 50% of property Catastrophic in affected area damaged or destroyed. Complete shutdown of 4 critical facilities for 30 days or more.
Negligible Less than 1% of area affected 1
Spatial Small Between 1 and 10% of area affected 2 20% Extent Moderate Between 10 and 50% of area affected 3
Large Between 50-100% of area affected 4
More than 24 hrs Self Explanatory 1
12-24 hours Self Explanatory 2 Warning 10% Time 6-12 hours Self Explanatory 3
Less than 6 hours Self Explanatory 4
Less than 6 hours Self Explanatory 1
Less than 24 hours Self Explanatory 2 Duration 10% Less than 1 week Self Explanatory 3
More than 1 week Self Explanatory 4
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5.2. Study Area Definition
The study area includes the unincorporated areas of Onslow County and all five municipalities: Holly Ridge, Jacksonville, North Topsail Beach, Richlands, and Swansboro. Onslow County (OC) is in the NC Emergency Management (NCEM) Eastern Branch (EB), and Federal Emergency Management Agency (FEMA) Region IV. Geographically it is located in SE North Carolina approximately 100 miles SE of Raleigh, and 30 miles N of Wilmington. It is bordered on the E by the Atlantic Ocean and Carteret County; on the S by the Atlantic Ocean and Pender County; on the W by Pender and Duplin Counties; and on the N by Jones County.
Onslow County consists of flat, gently rolling terrain, which slopes easterly from an altitude of 63 feet above sea level in the town of Richlands to near sea level at the town of North Topsail Beach. The average elevation is 23 feet. The County includes 27 miles of unspoiled coastline and a total land area of approximately 819 square miles or approximately 524,000 acres. Of this total, 157,000 acres make up US Marine Corps Installations located in the County.The City of Jacksonville is home to the County Seat, and the areas surrounding the City comprise the major population centers and growth area in the County.
5.2.1. Asset Inventory
An inventory of all of Onslow County’s assets was compiled in order to help identify and characterize those assets that may be potentially at risk to the identified hazards. By identifying these assets and their geographic location a relative risk and vulnerability for said assets can be determined. Two categories of assets are identified:
Improved Property – Includes all improved properties in both unincorporated areas of Onslow County and the incorporated jurisdictions according to local parcel data provided by Onslow County Tax Department. The information is listed by number of parcels, number of buildings, and total assessed value of improvements (buildings) that may be exposed to the identified hazards.
Critical Facilities – Includes all government buildings, medical facilities (both hospitals and EMS stations), fire stations, police stations, schools (with shelters identified), supportive and public infrastructure (airports, highways, bridges, dams, water & sewer facilities), and public and private utilities. Critical facilities are identified as those facilities which must function to protect the health, safety, and viability of the community and those facilities that provide essential services required to maintain or restart the overall function of the community.
The following tables provide detailed listings of the assets have been identified for inclusion in the vulnerability assessment. The list may be expanded in future updates to become more inclusive as better dtat becomes available.
5.2.2. Improved Property
Table 5.2 lists the number of parcels, estimated number of buildings, and total assessed value of improvements in Onslow County.
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Table 5.2: Improved Property in Onslow County Estimated Number Total Assessed Value Jurisdiction Number of Parcels of Buildings of Improvements Unincorporated 56,764 39,810 $7,094,839,810 Holly Ridge 2,686 1,003 $227,097,210 Jacksonville 15,583 14,677 $3,536,486,684 North Topsail 3,943 2,594 $804,012,460 Richlands 1,074 924 $163,296,910 Swansboro 2,004 1,668 $412,433,041 TOTAL 82,054 60,676 $12,238,166,115 Source: Onslow County Tax Office
5.2.3. Critical Facilities
Table 5.3 lists all fire stations, police stations, hospitals, emergency medical facilities (EMS & Rescue), government facilities, emergency shelters, airports, dams and wastewater treatment plants, utilities, public infrastructure and schools in Onslow County. The listings are separated out by the number of each facility within each jurisdiction and the unincorporated areas of the county. Figure 5.2 shows estimated critical facility locations within Onslow County.
Table 5.3: Critical Asset Inventory Location Number Fire Stations Holly Ridge 1 Jacksonville 5 North Topsail Beach 2 Richlands 1 Swansboro 1 Unincorporated 16 Police Stations Holly Ridge 1 Jacksonville 2 North Topsail Beach 1 Richlands 1 Swansboro 1 Unincorporated 0 Health Care (Hospitals, Urgent Care, Mental Health) Jacksonville 7 EMS Stations & Rescue Squads Holly Ridge 1 Jacksonville 2 North Topsail Beach 1
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Richlands 1 Swansboro 0 Unincorporated 11 Government Buildings Holly Ridge 2 Jacksonville 12 North Topsail Beach 2 Richlands 1 Swansboro 2 Unincorporated 2 Emergency Shelters Holly Ridge 0 Jacksonville 3 North Topsail Beach 0 Richlands 1 Swansboro 1 Unincorporated 3 Airports Holly Ridge 1 Unincorporated 5 Dams & Wastewater Treatment Plants Unincorporated 6 Schools Holly Ridge 0 Jacksonville 14 North Topsail Beach 0 Richlands 4 Swansboro 4 Unincorporated 18 Utilities Holly Ridge 2 Jacksonville 3 North Topsail Beach 1 Richlands 1 Swansboro 2 Unincorporated 16 Emergency Communications Towers Holly Ridge 0 Jacksonville 1 North Topsail Beach 0 Richlands 0 Swansboro 0 Unincorporated 4
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Figure 5.2: Asset Inventory for Onslow County
Source: Onslow County GIS
5.2.4. Population
The population of the County and the municipalities within the County is 185,220 (US Census 2013 estimates). Onslow County is the 11th most populated County in NC and is currently ranked as the fastest growing county (NC Office of State Budget and Management 2013). Onslow County sees a moderate increase in population
SECTION 5: VULNERABILITY ASSESSMENT 9 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 during tourist season and according to the Onslow County Tourism board the estimated peak seasonal population is around 200,000+. Table 5.4 provides a summary of population, land areas and densities for the planning areas.
Table 5.4: Population, Areas and Densities Density Per Square Mile Area in Square Miles Total of Land Area Jurisdiction Population Housing Total Water Land Units Population Housing Units Area Area Area Onslow County 185,220 909 142 767 74,227 242 97 Holly Ridge 1,758 3.8 0.1 3.76 734 468 195 Jacksonville 69,079 50.7 4.2 46.5 22,005 1,486 473 North Topsail Beach 736 10.6 4.2 6.4 2,454 115 383 Richalnds 1,654 1.6 0.0 1.6 709 1,034 443 Swansboro 2,993 2.2 0.1 2.1 1,499 1,425 690
Sources: US Census: Gazetteer
5.2.5. Social Vulnerability
According to the 2010 US Census the median age for Onslow County is 25.8 which is much younger than the North Carolina median age of 37.4 and the average household size in Onslow County is 2.0 persons per household (33.9%). Nearly 18% of the population ranges between 20-24 years old and 9.6% of the population is over the age of 62 (approximately 17,781) and 9.4% are under the age of 5 (approximately 17,410). The median household income level is $45,182 with 21.1% of the population earning between $50,000 and $74,999. Approximately 22.3% of the population earns an income below $25,000 with 6.8% earning less than $10,000. Approximately 11.7% of the residents are listed as veterans. Approximately 7% (13,386) of the population age 16 and older are listed as holding disability status.
Figure 5.3 illustrates the population density by census tract in Onslow County based on the 2010 U.S. Census. Based on the map
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Figure 5.3: Population Density by Census Tract
Source: U.S. Census; Onslow County GIS
5.2.6. Development Trends An important factor in determining mitigation options that will influence future land use decisions is to develop a general analysis of current land uses and development trends. Utilizing this information along with population statistics, projected growth and social vulnerability helps develop a complete picture of vulnerability.
Onslow County and its municipalities have all developed land use ordinances to help regulate land use and guide future development patterns. Onslow County and its municipalities have each develop maps to help better visualize vulnerabilities. Each map can be located throughout the document as identified in Table 5.5.
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Table 5.5: Map Reference Locations Location Map Page Map: Onslow County with Municipalities & ETJ’s Figure 4.1 (pg. 62) Map: Flood Hazards Figure 4.17 (pg. 109) Onslow County Map: Flood Hazard & Repetitive Loss Figure 5.6 Map: Flood Hazard & Critical Facilities Figure 5.4 Map: Critical Facilities Figure 5.2 (pg. 128) Map 1: City Limits & ETJ Annex 1-51 Map 2: CAMA Land Use Map Annex 1-52 Map 3: Zoning Annex 1-53 Jacksonville Map 4: Flood Zone Map Annex 1-54 Map 5: Critical Facilities Annex 1-55 Map 6: Repetitive Loss Areas Annex 1-56 Map 1: City Limits & ETJ Annex 2-26 Map 2: Flood Hazard Annex 2-27 Map 3: Land Use Annex 2-28 Map 4: Flood Hazard & Land Use Annex 2-29 Map 5: Zoning Annex 2-30 Holly Ridge Map 6: Flood Hazard & Zoning Annex 2-31 Map 7: Repetitive Loss Areas Annex 2-32 Map 8: Flood Hazard & Repetitive Loss Annex 2-33 Map 9: Flood Hazard & Critical Facilities Annex 2-34 Map 10: Town SLOSH Map Annex 2-35 Map 1: City Limits & ETJ Annex 3-41 Map 2: Flood Hazards Annex 3-42 Map 3: Land Use Annex 3-43 Map 4: Flood Hazard & Land Use Annex 3-44 Map 5: Zoning Annex 3-45 North Topsail Beach Map 6: Flood Hazard & Zoning Annex 3-46 Map 7: Repetitive Loss Areas Annex 3-47 Map 8: Flood Hazard & Repetitive Loss Annex 3-48 Map 9: Flood Hazard & Critical Facilities Annex 3-49 Map 10: Town SLOSH Map Annex 3-50 Map 1: City Limits & ETJ Annex 4-34 Map 2: Flood Hazards Annex 4-35 Map 3: Land Use Annex 4-36 Map 4: Flood Hazard & Land Use Annex 4-37 Richlands Map 5: Zoning Annex 4-38 Map 6: Flood Hazard & Zoning Annex 4-39 Map 7: Repetitive Loss Areas Annex 4-40 Map 8: Flood Hazard & Repetitive Loss Annex 4-41 Map 9: Flood Hazard & Critical Facilities Annex 4-42 Map 1: ETJ & Town Limits Annex 5-43 Map 2: Flood Hazards Annex 5-44 Map 3: Land Use Annex 5-45 Swansboro Map 4: Flood Hazard & Land Use Annex 5-46 Map 5: Zoning Annex 5-47 Map 6: Flood Hazard & Zoning Annex 5-48
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Map 7: Repetitive Loss Areas Annex 5-49 Map 8: Flood Hazard & Repetitive Loss Annex 5-50 Map 9: Flood Hazard & Critical Facilities Annex 5-51
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ATMOSPHERIC HAZARDS
5.3. Drought & Heat wave
PRI Value: 1.8 Annualized Loss Estimate: Negligible
Drought can impact natural systems as well as the ability of cities and towns to function effectively. Effects can include impacts to crops, wildlife, livestock, and the availability of water supplies for residential and commercial use. The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.6 and the PRI value is 1.8 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.6: Qualitative Assessment for Drought & Heat wave Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Likely Minor Negligible 12-24 hrs Less than 24 hrs
Due to a lack of available data on historic losses across the sectors caused by drought in Onslow County this estimation is limited to agricultural claims. Agriculture concerns, such as poultry and swine operations are most susceptible to extreme heat. Extreme heat can and does cause extensive poultry deaths. Livestock, while susceptible to extreme heat can be cared for easier than poultry. According to the Natural Resources Defense Council (referred by: National Drought Mitigation Center (NDMC) the annualized crop losses due to drought for North Carolina was $77,754,113 in federal aid with Onslow County receiving $522,157 in Federal Crop Insurance claims, the majority of which were reported as excessive moisture/precipitation/rain.
5.3.1. Asset Vulnerability
All assets across Onslow County are exposed to the effects of drought and heat wave and may exceed total figures listed in Table 5.2. It is unlikely that this hazard will cause structural damages to critical facilities. Onslow County pulls water from aquifers and deep water wells and has felt minimal impact in the recent droughts.
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5.4. Severe Thunderstorm & Hail
PRI Value: 2.4 Annualized Loss Estimate: Hail-none (NCDC 1955-2013); Severe Thunderstorm - $4,645 (NCDC 1965-2013)
Historical data shows that Onslow County has a high probability of severe thunderstorm and hail activity on an annual basis. The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.7 and the PRI value is 2.4 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.7: Qualitative Assessment for Severe Thunderstorm & Hail Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Highly Likely Minor Small Less than 6 hrs Less than 6 hrs
Because it cannot be predicted where severe thunderstorm and hail events will occur it is impossible to map geographic boundaries for this hazard and all existing and future buildings, facilities, and populations are considered equally exposed to this hazard and could potentially be impacts.
Given the lack of historical loss data on significant hail damage occurrences in Onslow County, it is assumed that while one major event could potentially result in significant losses due to hail, annualizing structural losses over a long period of time would most likely yield a negligible annualized loss estimates.
5.4.1. Asset Vulnerability
All inventoried assets (Table 5.3) in Onslow County are equally exposed to the effects of Hail. Anticipated damages to this hazard are expected to be minimal to inventoried assets.
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5.5. Hurricanes and Coastal Storms (Includes Nor’easters)
PRI Value: 2.9 Annualized Loss Estimate: $51 million (NCDC 1996-2013) Historical records show that Onslow County, and its jurisdictions, are vulnerable to the damaging effects of hurricane, tropical storms and Nor’easters. According to NOAA records, 104 hurricanes and tropical storms have passed within a 75 mile radius of Onslow County since 1851. Of the 104 passing near Onslow 76 are recorded as having passed through or made landfall in the county. During a Category 3 slow moving hurricane, approximately 18,764 acres could be inundated as compared to 21,377 acres for a fast moving Category 3 hurricane. Onslow County is more vulnerable to fast moving hurricanes (hurricanes that move at a speed that is greater than or equal to 15 mph) than it is to slow moving hurricanes (hurricanes that move at a speed that is less than 15 mph). The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.8 and the PRI value is 2.9 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.8: Qualitative Assessment for Hurricane & Coastal Storm Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Likely Critical Large More Than 24 hrs Less Than 24 hrs
Hurricanes, tropical storms, and Nor’easters are often large in size and often impact large geographic areas. All existing and future buildings, facilities and populations are considered to be exposed to this hazard and could potentially be impacted. Often, other hazards will co-occur during these types of storms. These include flooding, erosion, tornadoes and storm surge. HAZUS-MH was utilized to estimate potential losses from hurricane winds. Currently HAZUS-MH is not capable of developing an estimation model for the cumulative losses incurred from the simultaneous flooding, erosion, storm surge and tornadoes. Storm surge is addressed individually later in this section.
Detailed loss estimates for the hurricane and tropical storm hazards (as related to winds) were developed based on the probabilistic scenarios using HAZUS-MH (Level 1 scenario). Table 5.9 shows estimates of potential losses for hurricane force winds.
Table 5.9: Hurricane Winds Potential Loss Estimates Level of Event Estimated Losses 50 Year Storm (95-110 mph Winds) $229,212 100 Year Storm (110-125 mph Winds) $1,319,567 500 Year Storm (125-140 mph Winds) $3,536,760 5.5.1. Asset Vulnerability All assets in Onslow County and its jurisdictions are exposed to hurricane, tropical storm and Nor’easter hazards. Damages may exceed the estimates given for any particular storm due to varying factors that influence each event. Specific vulnerabilities of each asset will depend greatly on their design and the mitigation measures, if any, that are in place. Continued enforcement of building codes, flood ordinances and other regulatory policies and tools are designed to help mitigate the effects and help minimize future losses.
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5.6. Tornado
PRI Value: 2.1 Annualized Loss Estimate: $249,939 (NCDC 1950-2013)
Historical records show that Onslow County is vulnerable to tornado activity. Tornado activity is often associated with other hazards such as Severe Thunderstorm and Hurricane. The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.10 and the PRI value is 2.1 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.10: Qualitative Assessment for Tornado Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Likely Minor Small Less Than 6 hrs Less Than 6 hrs
Because it cannot be predicted where a tornado will strike, it is not possible to map geographic boundaries for this hazard or produce detailed loss estimates. Therefore, all existing and future buildings, facilities and populations are considered to be exposed to this hazard and could potentially be impacted. According to the National Climatic Data Center, over a 59 year time span (1959-2013) Onslow County incurred almost $15 million in losses due to tornado.
5.6.1. Asset Vulnerability
Given the history and likely probability of tornado activity and an inability to predict an affected area, all assets in Onslow County are considered exposed to this hazard. Specific vulnerabilities for each asset will be greatly dependent upon their design and any mitigation measures, if existing, in place. Damages may exceed the average annual losses due to variability of the size and intensity of the storm.
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5.7. Winter Storm
PRI Value: 2.1 Annualized Loss Estimates: $8,529 (NCDC 1996-2013)
Historical records indicate that Onslow County is vulnerable to winter storm. The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.11 and the PRI value is 2.1 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.11: Qualitative Assessment of Winter Storm Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Possible Minor Large More Than 24 hrs Less Than 1 Week
Because winter storms often affect large geographic areas, it is not possible to map geographic boundaries for this hazard or produce detailed loss estimates. Therefore, all existing and future buildings, facilities and populations are considered to be exposed to this hazard and could potentially be impacted. According to the National Climatic Data Center, there were 22 occurrences of winter storm, winter weather, sleet, and frost/freeze over a 17 year period.
5.7.1. Asset Vulnerability
Due to the wide geographical scope of winter storms all assets in Onslow County are considered exposed to this hazard. Damages may exceed the average annual losses due to variability of the size and intensity of the storm.
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GEOLOGIC HAZARDS 5.8. Earthquake
PRI Value: 1.3 Annualized Loss Estimates: Negligible
Historical records indicate that Onslow County is vulnerable to winter storm. The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.12 and the PRI value is 1.3 (on a scale of 1 to 4, with 4 being the highest risk level). Table 5.12: Qualitative Assessment of Earthquake Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Unlikely Minor Negligible Less Than 6 hrs Less Than 6 hrs
As is referenced in the Hazard Identification Section (Section 4) Onslow County’s risk to earthquakes is considered limited. HAZUS-MH was utilized to determine estimated losses from earthquakes for the 100, 500 and 1,000 year return periods. Table 5.13 provides a summary of dollar losses and Table 5.14 shows generalized building damage estimates based on percentage of damage (by damage state).
Table 5.13: Earthquake Potential Loss Estimates Level of Event Estimated Losses 100 Year Event Less than $1 million 500 Year Event $5,780,000 1,000 Year Event $26,800,000
Table 5.14: Estimates of Potential Building Damage by Damage State Building Occupancy Type Slight Moderate Extensive (# of buildings) 500 yr 1,000 yr 500 yr 1,000 yr 500 yr 1,000 yr Single Family Residential 373 1,334 58 251 5 23 Other Residential 506 1,343 151 558 5 28 Commercial 34 102 10 37 1 5 Industrial 10 30 3 11 0 1 Agricultural 3 8 1 2 0 0 Education 1 4 0 1 0 0 Government 1 3 0 1 0 0 Religious/Non-Profit 4 11 1 4 0 1 TOTAL 932 2,835 865 865 11 58 5.8.1. Asset Vulnerability
Due to the wide geographical scope of earthquakes all assets in Onslow County are considered exposed to this hazard. Damages from earthquake hazard may vary significantly based on the location of the epicenter, building construction and magnitude of the event.
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5.9. Landslide and Sinkhole
PRI Value: 1.6 Annualized Loss Estimate: Negligible
As documented in Section 4, historical records indicate no evidence of landslide events in Onslow County and minor evidence of sinkhole events. The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.15 and the PRI value is 1.6 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.15: Qualitative Assessment of Landslide & Sinkhole Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Possible Minor Negligible Less Than 6 hrs Less Than 6 hrs
There is currently only one recorded event of loss due to sinkhole at an estimated cost of $125,000 (home was condemned and removed). Given the lack of historical data on landslide and sinkhole damages in Onslow County it is assumed that singular events may result in significant damages or losses but long term loss projections would be very low.
5.9.1. Asset Vulnerability
While landslide and sinkhole occurrences are rare, the vast majority of the county overlies a karst formation as is documented in Section 4. Therefore, all identified assets are considered to be vulnerable.
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5.10. Tsunami
PRI Value: 2 Annualized Loss Estimates: Negligible
As documented in Section 4, historical records indicate no evidence of tsunami events in Onslow County. The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.16 and the PRI value is 2 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.16: Qualitative Assessment of Tsunami Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Unlikely Limited Small 6-12 hrs More Than 1 Week
No standardized models exist for determining loss estimation secondary to tsunami for the East Coast. Currently, The Center for Applied Coastal Research at the University of Delaware, are working to develop tsunami inundation maps for the East Coast however, maps for North Carolina have not yet been created. As a general guideline though, vulnerability to tsunami can be compared to vulnerability to storm surge inundation and flooding.
Given the lack of historical data on tsunami occurrences to affect Onslow County it is assumed that while a single event may cause significant losses, long term projected losses would be very low.
5.10.1. Asset Vulnerability
All current and future assets that are in coastal or riverine areas could potentially be exposed to the tsunami hazard.
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HYDROLOGIC HAZARDS
5.11. Coastal & Riverine Erosion
PRI Value: 2.2 Average Annual Loss: Negligible As documented in the Hazard Identification section Onslow County is vulnerable to the effects of erosion, most significantly coastal erosion. The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.17 and the PRI value is 2.2 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.17: Qualitative Assessment of Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Highly Likely Minor Negligible More Than 24 hrs More Than 1 Week
Coastal Erosion is the primary area of erosion hazard in Onslow County. Unlike most other hazards, coastal erosion is a hazard best described as a slow naturally occurring process that progressively decreases the shoreline over an extended period of time. While significant erosion may be caused in a single event, such as hurricane and tropical storm, most erosion rates are measured on the long-term impact. Shoreline restoration projects and hazard mitigation efforts can complicate the ability to accurately determine hazard areas due to erosion as those areas of highest concern are often areas that receive re-nourishment or stabilization efforts. The areas of highest erosion, according to the North Carolina Division of Coastal Management, are primarily Onslow Beach (Camp Lejeune) and Bear Island (Hammock Beach State Park). For documentation purposed this assessment will focus on improved structures in North Topsail Beach and Bear Island.
The determination of at-risk properties was determined by developing the average erosion rates for several sections of coastline. These average rates were then projected by 20 years of continuous erosion. This developed a potential constant erosion of 60 feet of lost shoreline over the 20 years. It should be noted this factor does not account for storm related loss, restoration or accretion. Applying the 60 foot setback Onslow County GIS ran a spatial analysis to determine a total count and improved values of at-risk properties that fall within the 20 year erosion risk hazard.
The analysis yielded 57 properties totaling over $8,120,890.00 within the 20 year at-risk zone. Table 5.18 identifies properties, by jurisdictions, which were identified. While these properties, for the purpose of this assessment, are identified as being threatened by erosion, it is unlikely that any significant damages will occur on an annual basis. Table 5.18: Erosion Risk Number of At Risk Value of Improvements Location Structures (Structures) At Risk North Topsail Beach 57 $8,120,890.00 Surf City 0 $0.00 5.11.1. Asset Vulnerability Those assets at greatest risk are those closest to the shoreline. This analysis did not indicate any at risk identified assets. Those assets on North Topsail Beach are all located beyond the 60 foot study area.
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5.12. Dam & Levee Failure
PRI Value: 2.1 Average Annual Loss: Negligible
Onslow County has no recorded history of dam failure as identified in Section 4. The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.19 and the PRI value is 2.1 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.19: Qualitative Assessment of Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Unlikely Limited Small Less Than 6 hrs More Than 1 Week
Onslow County currently has six dams that are recorded with the National Dam Inventory and North Carolina Dam Inventory, produced by the NCDENR, Division of Energy, Mineral and Land Resources. Of these three are water and wastewater treatment facilities and three are privately owned recreational ponds. For the purposes of this vulnerability study only the three HIGH hazard dams were assessed for losses. For each facility a one- mile radius was developed and all properties falling within that radius were counted. None of the three dams assessed are subjected to inundation from a single direction. Table 5.20 identifies dam failure exposure for each facility.
Table 5.20: Dam Failure Exposure Dam Name Number of Total Assessed Value of Buildings Improvements (Buildings) Jacksonville Wastewater Lagoon 321 $44,128,230 Jacksonville LTS-South Storage Lagoon North Topsail Water & Sewer Lagoon (Pluris) 96 $9,524,270
There is no historical record of unintentional dam failre in Onslow County. It should be assumed that a signle failure of one of the three HIGH hazard dams could result in significant loss, however, estimated losses over time would be considered negligible.
5.12.1. Asset Vulnerability
The analysis indicated that one critical facility, a school, is just outside the one mile radius and could potentially be vulnerable. Damages could exceed the estimates of the analysis and therefore the asset should be considered.
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5.13. Flooding
PRI Value: 3 Annualized Loss Estimate: $485,000 (NCDC 1995-2013)
Approximately 112,245 acres, or 21%, of the County is located within the 100-year floodplain. Approximately 21% of the 100-year floodplain is developed and tax valued at approximately $2.374 billion. There are approximately 6,941 structures located within the 100-year floodplain. The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.21 and the PRI value is 3 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.21: Qualitative Assessment of Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Highly Likely Limited Moderate 6-12 hrs Less Than 1 Week
The assessment for flood hazard includes the qualitative assessment and a GIS based analysis of identified floodplains developed by FEMA in combination with local tax assessment records. At-risk values (exposure) were determined by compiling the values of all assessed improvements (buildings) that were confirmed to be within the following Flood Zones:
A/AE (1% annual chance of flood) Zone VE (1% annual chance coastal flood zone with associated wave action) Zone X-shaded (0.2% annual chance of flood)
Table 5.22 lists participating jurisdictions and the number of improved properties located within each of the special flood hazard areas along with the values of the structures identified.
Table 5.22: Onslow County Flood Exposure of Improved Properties Participating Area Number of Buildings at Risk Value of Buildings at Risk At-Risk (1.0 Percent Annual Chance Flood) (A – 100yr flood) Holly Ridge 0 $ - Jacksonville 163 $ 30,260,000.00 North Topsail 382 $ 55,747,250.00 Richlands 24 $ 3,422,160.00 Swansboro 59 $ 6,146,260.00 Unincorporated 4487 $ 593,186,220.00 TOTAL: 5115 $ 688,761,890.00 At-Risk (Coastal VE Zone) Holly Ridge 0 $ - Jacksonville 0 $ - North Topsail 2180 $ 348,942,380.00
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Richlands 0 $ - Swansboro 8 $ 1,402,620.00 Unincorporated 215 $ 38,698,690.00 TOTAL: 2403 $ 389,043,690.00 At-Risk (0.2 Percent Annual Chance Flood) (B or Shaded X – 500yr flood) Holly Ridge 0 $ - Jacksonville 252 $ 59,834,610.00 North Topsail 0 $ - Richlands 16 $ 3,531,620.00 Swansboro 36 $ 4,200,930.00 Unincorporated 1888 $ 246,449,730.00 TOTAL 2192 $ 314,016,890.00 Total At-Risk 9710 $ 1,391,822,470.00
5.13.1. Asset Vulnerability
There are a total of 21 inventoried assets for Onslow County that are vulnerable to the effects of flood. This includes: 6 lift stations, 3 waste water treatment plants, 1 water treatment facility, 3 fire departments, 1 EMS/Rescue station, 2 public works facilities, 1 law enforcement facility and 1 government building. Figure 5.4 shows inventoried assets in relation to special flood hazard areas (SFHA’s) identified by FEMA. It should be noted that the flood hazard may inflict greater damage than what is presented in this assessment as a result of extreme flood events.
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Figure 5.4: SFHA’s and Critical Assets
Source: Onslow County GIS
5.13.2. NFIP Statistics and Repetitive Loss
Onslow County has identified six generalized flood damage impact areas that are located adjacent to the following water bodies: Stump Sound, Chadwick Bay, Bear Creek, Queens Creek, and Cowford Landing. According to the Federal Emergency Management Agency flood insurance policy records, as of May 2014, there have been more than 3,245 flood losses reported in Onslow County through the National Flood Insurance Program since 1978. These losses have totaled over $40 million in claims payments. These losses include both inland and coastal flood events. It should be noted that these numbers include only those losses to structures that were insured, reported and paid out through NFIP policies. It is highly probable that additional flood losses
SECTION 5: VULNERABILITY ASSESSMENT 26 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 have occurred in Onslow County that were uninsured or not reported. Table 5.26 provides details for each jurisdiction with regard to the community’s date of entry into the National Flood Insurance Program (NFIP), date of the community’s current effective Flood Insurance Rate Map (FIRM), number of flood insurance policies in place, amount of coverage, total losses and dollar amounts of payments. The table also includes the number of repetitive loss properties identified through separate databases for each jurisdiction, as defined by NFIP.
FEMA defines a repetitive loss (RL) property as any insurable building for which two or more claims of more than $1,000 were paid by the NFIP within any rolling 10 year period since 1978. A repetitive loss property may or may not be currently insured by the NFIP. Severe Repetitive Losses (SRL) are classified as any property that has at least four claims payments, each over $5,000 and a cumulative amount that exceeds $20,000 or any property with at least two separate claims payments in which the cumulative amount of the building portion exceeds the market value of the building.
According to the North Carolina Emergency Management, Onslow County has 446 repetitive loss properties and 29 severe repetitive loss properties. Of the repetitive loss properties, 20 are in the City of Jacksonville, 254 in the Town of North Topsail Beach, 21 in the Town of Swansboro and 151 in the unincorporated areas of the county. Of the severe repetitive loss properties 20 are in North Topsail Beach, 2 are in Swansboro, and 4 are in the unincorporated areas of Onslow County. Total losses paid for all of the RL’s and SRL’s is approximately $25 million.
Table 5.26: NFIP Statistics and Repetitive Loss Properties NFIP Current Community Policies Amount of Total Entry Effective Total Payments Name in Force Coverage Losses Date Map Holly Ridge 11/03/2005 02/16/2007 45 $ 9,014,000.00 1 $ 7,231.05 Jacksonville 02/15/1985 02/16/2007 733 $ 196,517,400.00 144 $ 1,784,230.08 North Topsail Beach 07/02/1987 02/16/2007 1308 $ 247,487,100.00 1214 $ 14,571,476.53 Richlands 07/02/1987 02/16/2007 25 $ 6,344,000.00 1 $ 6,685.92 Swansboro 10/18/1983 02/16/2007 170 $ 45,623,000.00 98 $ 2,165,835.84 Onslow County 07/02/1987 02/16/2007 2087 $ 528,830,100.00 1787 $ 22,070,474.74 TOTALS: 4368 $ 1,033,815,600.00 3245 $ 40,605,934.16
Source: FEMA
Figure 5.6 illustrates the general locations of repetitive loss properties in Onslow County and participating jurisdictions. It should be noted that NFIP repetitive loss data is protected under the Federal Privacy Act of 1974 (5.U.S.C. 552a), which prohibits personal identifiers (i.e. owners names, addresses, etc...) from being published in local hazard mitigation plans.
Figure 5.6: Flood Zones and Repetitive Loss Areas
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Source: Onslow County GIS
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5.14. Storm Surge
PRI Value: 2.4
The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.27 and the PRI value is 2.4 (on a scale of 1 to 4, with 4 being the highest risk level). No annualized loss estimates could be determined for this hazard due to a lack of historical loss documentation.
Table 5.27: Qualitative Assessment of Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Likely Limited Moderate More Than 24 hrs Less Than 24 hrs
Storm surge is a hazard closely ties with hurricanes and differs from other coastal flood events. Coastal flood and coastal erosion, both independent of hurricane and coastal storm surge, are covered in those respective sections. To determine exposure estimates and potential losses for Onslow County a GIS-based analysis was utilized. This analysis involved running various SLOSH (Sea, Lake, and Overland Surges from Hurricanes) models to estimate storm surges resulting from historical and hypothetical hurricanes. Storm surge inundation areas were then overlaid with parcel data and building footprint data to determine the number and value of at risk properties in Onslow County. Storms were analyzied by both category and fast versus slow moving. Table 5.28 lists the number of properties determined to be in storm surge inundation areas and the improved values for these structures.
Table 5.28: Number and Values of Improved Properties At-Risk to Storm Surge
Number of Total Assessed Value of Number of Total Assessed Value of Storm Surge Properties Improvements (Buildings) Properties Improvements (Buildings) Inundation Zone
SLOW MOVING FAST MOVING Category 1 & 2 Holly Ridge 10 $ 2,130,720.00 10 $ 2,130,720.00 Jacksonville 365 $ 32,380,600.00 365 $ 32,380,600.00 North Topsail 2520 $ 400,484,150.00 2520 $ 400,484,150.00 Richlands 0 $ - 0 $ - Swansboro 311 $ 45,916,580.00 311 $ 45,916,580.00 Unincorporated 2061 $ 270,746,350.00 2333 $ 325,115,030.00 TOTAL 5267 $ 751,658,400.00 5539 $ 806,027,080.00 Category 3 Holly Ridge 10 $ 2,130,720.00 10 $ 2,130,720.00 Jacksonville 365 $ 32,380,600.00 365 $ 32,380,600.00 North Topsail 2520 $ 400,484,150.00 2520 $ 400,484,150.00 Richlands 0 $ - 0 $ - Swansboro 311 $ 45,916,580.00 311 $ 45,916,580.00
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Unincorporated 2671 $ 358,751,250.00 3198 $ 442,936,640.00 TOTAL 5877 $ 839,663,300.00 6404 $ 923,848,690.00 Category 4 & 5 Holly Ridge 10 $ 2,130,720.00 23 $ 4,161,890.00 Jacksonville 392 $ 36,359,270.00 392 $ 36,359,270.00 North Topsail 2520 $ 400,484,150.00 2520 $ 400,484,150.00 Richlands 0 $ - 0 $ - Swansboro 311 $ 45,916,580.00 311 $ 45,916,580.00 Unincorporated 3252 $ 447,806,080.00 4948 $ 643,813,720.00 TOTAL 6485 $ 932,696,800.00 8194 $ 1,130,735,610.00
5.14.1. Asset Vulnerability
It should be noted that NOAA has separated storm surge inundation from the Saffir-Simpson Hurricane Scale and severe inundation can occur with even Category 1 and 2 storms as is discussed in the Hazard Identification section (Section 4), however for the purposes of this assessment SLOSH models (a category and tide based inundation model) were utilized. The majority of assets are located in areas that would only be inundated in major hurricanes (Category 3 and above).
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OTHER HAZARDS
5.15. Wildfire
PRI Value: 2.5 Average Annual Loss: Negligible
The qualitative assessment performed utilizing the PRI tool is summarized in Table 5.29 and the PRI value is 2.5 (on a scale of 1 to 4, with 4 being the highest risk level).
Table 5.29: Qualitative Assessment of Category / Degree of Risk
Probability Impact Spatial Extent Warning Time Duration
Highly Likely Minor Small Less Than 6 hrs Less Than 24 hrs
The data used to determine location and spatial extent of wildfire risk in Onslow County was based on data obtained from the Southern Wildfire Risk Assessment (SWRA) provided by the North Carolina Division of Forest Resources.
Figure 5.7: Areas of Wildfire Risk
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To estimate wildfire exposure the above referenced map was combined with GIS parcel data to determine the number of improved footprints within the moderate and high risk areas and summing to total assessed values for the properties. Table 5.30 summarizes this information.
Table 5.30: Total Exposure of Improved Properties to Wildfire Total Assessed Value of Hazard Zone Number of Properties Improvements (Buildings) at risk Moderate Wildfire Risk Area 21,505 $2,467,385,825
High Wildfire Risk Area 31,888 $4,237,159,849
No annualized loss estimates could be determined for this hazard due to a lack of historical data on wildfire occurrences resulting in structural losses. However, based on the data available it is assumed that structural losses over a long period of time would result in negligible annualized losses.
5.15.1. Asset Vulnerability
There are 00 inventoried assets in Onslow County determined to be vulnerable to the effects of wildfire. This includes:
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5.16. Conclusions On Hazard Vulnerability
Future vulnerability can be thought of as a measure of the extent to which people and property would be harmed by a hazardous event if a projected scenario of development were to occur. An area's vulnerability changes with time. If current development patterns are projected into the future, it is possible to develop estimates of the population and amount of development that will exist in an area at some future point. Thus, given an increasing population and increasing development, it might appear that an area would have a greater vulnerability to hazards in the future. Vulnerability will increase significantly if development occurs in areas particularly susceptible to natural hazards. A general indicator of Onslow County's future vulnerability lies in its projected population growth. Table 5.31 provides a summary of anticipated population growth through the year 2030 and Table 5.32 provides a summary of current and potential conditions for Onslow County.
Table 5.31: Population Projections for Onslow County Jurisdiction 2010 2020 2030 Net Gain Holly Ridge 1,268.00 1,553.55 1,794.51 526.51 Jacksonville 70,145.00 85,941.65 99,271.20 29,126.20 North Topsail Beach 743.00 910.32 1,051.51 308.51 Richlands 1,520.00 1,862.30 2,151.15 631.15 Surf City (part) 1,618.00 1,982.37 2,289.84 671.84 Swansboro 2,663.00 3,262.71 3,768.75 1,105.75 Total Municipalities 77,957.00 95,512.92 110,326.97 32,369.97 Total Unincorporated 99,815.00 122,296.08 141,275.03 41,460.03 Areas Total County 177,772.00 217,809.00 251,602.00 73,830.00 Projected Growth Rates 22.52% 15.51% Note: Total County projections are based on North Carolina Office of State Planning data. Municipal estimates were based on the overall projected growth rate for the Total County data. Municipal estimates extrapolated by Onslow County Emergency Services.
Table 5.32: Current and Potential Conditions for Onslow County Current Conditions Potential Future Conditions (2020) Projected Number Current Value/ of Private Buildings Type of Number of Existing Projected Loss (If developed under Development Private Buildings (structure value) existing policies) Projected Value Single-Family 30,835 $5,003,821,570 43796 $6,459,774,870 Residential Multi-Family 2075 $444,423,890 3067 $493,232,790 Residential Commercial 1582 $770,842,900 1740 $847,927,190 Industrial 16 $26,897,390 19 $14,468,815 Other (Vacant) 18201 $1,035,178,710 18946 $837,435,810 Subtotal 52,709 $7,281,164,460 67567 $8,652,839,475
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As indicated in the above table, Onslow County's population is anticipated to increase approximately 42% between the years 2010 and 2030. As a result, Onslow County's population in the year 2030 may be approximately 251,602. It should be noted, that these projections are based on percent increase of base survival rates. It does not account for net migration or fluctuations in birth or death rates. These numbers should be viewed as gross estimations of predicted growth and actual population statistics may be larger or smaller. While it is impossible to predict exactly how much of the County's new development will occur in the 100-year floodplain, some will certainly occur. Consequently, the County's vulnerability to hurricanes, nor'easters, and flooding will increase due to population growth unless mitigation actions are taken.
This vulnerability assessment provides for significant findings that will allow the Hazard Mitigation Planning Committee to prioritize hazard risk and propose mitigation strategies and actions. This is accomplished by improving our understanding of the complexities and dynamics of risk, how levels of risk can be measured, and the factors that influence risk. The data and findings will help build a baseline for policy development and comparison of mitigation alternatives by creating a method to compare risk changes over time. The data also helps quantify hazard risk relative to other hazards. The ranking will allow for a systematic framework to compare and prioritize the very disparate hazards.
Table 5.33 summarized the qualitative assessments for each hazard as presented throughout this section.
Table 5.33: Summary of Qualitative Assessment Category / Degree of Risk Hazard Probability Impact Spatial Extent Warning Time Duration Atmospheric Hazards
Drought and Heat wave Likely Minor Negligible 12-24 hrs Less than 24 hrs Severe Thunderstorm / Hail Highly Likely Minor Small Less than 6 hrs Less than 6 hrs Hurricane & Coastal Storm Likely Critical Large More than 24 hrs Less than 24 hrs Tornado Likely Minor Small Less than 6 hrs Less than 6 hrs Winter Storm Possible Minor Large More than 24 hrs Less than 1 week Geological Hazards
Earthquake Unlikely Minor Negligible Less than 6 hrs Less than 6 hrs Landslide & Sinkhole Possible Minor Negligible Less than 6 hrs Less than 6 hrs Tsunami Unlikely Limited Small 6-12 hrs More than 1 week Hydrologic Hazards
Erosion Highly Likely Minor Negligible More than 24 hrs More than 1 week Dam & Levee Failure Unlikely Limited Small Less than 6 hrs More than 1 week Flood Highly Likely Limited Moderate 6-12 hrs Less than 1 week Storm Surge Likely Limited Moderate More than 24 hrs Less than 24 hrs Other Natural Hazards
Wildfire Highly Likely Minor Small Less than 6 hrs Less than 24 hrs
Table 5.34 summarizes annualized loss estimates that were generated for each identified hazard based on the quantitative assessment and compares them with the PRI Values determined based on the qualitative assessment.
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Table 5.34: Comparison of Annualized Loss Estimates and Priority Risk Index Values Quantitative Assessment Findings Qualitative Assessment Findings Hazard Annualized Loss Estimates Hazard PRI Score Hurricane & Coastal Storm $51,000,000 Flood 3 Flood $485,000 Hurricane & Coastal Storm 2.9 Tornado $249,939 Wildfire 2.5 Winter Storm $8,529 Severe Thunderstorm / Hail 2.4 Severe Thunderstorm / Hail $4,645 Storm Surge 2.4 Storm Surge N/A Erosion 2.2 Wildfire Negligible Tornado 2.1 Erosion Negligible Winter Storm 2.1 Dam & Levee Failure Negligible Dam & Levee Failure 2.1 Tsunami Negligible Tsunami 2 Drought and Heat wave Negligible Drought and Heat wave 1.8 Landslide & Sinkhole Negligible Landslide & Sinkhole 1.6 Earthquake Negligible Earthquake 1.3
The conclusions drawn from the qualitative and quantitative assessments, combined with final determinations from the Hazard Mitigation Planning Committee were grouped into three categories for a final summary of hazard risk for Onslow County based on a High, Moderate, and Low risk designation. It should be noted that rankings are based on best available data and some hazards may be grouped as low risk that due to varying occurrence and magnitude could result in significant risk and loss.
Table 5.35: Conclusions on Hazard Risk
Flood Hurricane & Coastal Storm Severe Thunderstorm / Hail HIGH RISK Storm Surge Tornado Winter Storm
Wildfire Dam & Levee Failure MODERATE RISK Landslide & Sinkhole Drought and Heat wave
Erosion LOW RISK Tsunami Earthquake
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6. CAPABILITY ASSESSMENT
In the mitigation planning process, it is not only important to identify what ELEMENTS C144 CFR Part hazards affect a community and what vulnerabilities exist in a community 201.6(c)(3): but it is also important to identify the resources the community has available The Hazard Mitigation Strategy to prepare for, mitigate against, respond to and recover from those hazards. that provides the jurisdictions Section 7 of this plan will discuss the capability assessment. This section will blueprint for reducing the potential losses identified in include the the following sections: the risk assessment, based on existing authorities, policies, 6.1 What is a Capability Assessment programs, and resources, and its ability to expand on and 6.2 Capability Assessment Findings improve these existing tools.
6.3 Conclusions on Local Capability
6.1. What is a Capability Assessment
A capability assessment is an evaluation of the government structure, political framework, legal jurisdiction, fiscal status, policies and programs, regulations and ordinances, and resources available. Each category is evaluated for its strengths and weaknesses in responding to/ preparing for and mitigating the effects of the identified hazards. Integral to any planning process is to establish which goals, objectives and/or actions are feasible based on an understanding of the capacity of the assigned agency to implement them. A capability assessment helps to determine which mitigation actions are practical and most likely to be implemented over time given a local jurisdiction regulatory framework, administrative and technical support, fiscal resources and current political climate.
The capability assessment has two components: 1) an inventory of local jurisdictions relevant plans, ordinances and programs and 2) an analysis of their capacity to execute them. Careful examination of these capabilities will help identify any existing gaps or weaknesses within government activities that could potentially hinder proposed mitigation activities or exacerbate hazard vulnerability.
A capability assessment is an integral part of the hazard mitigation planning process in which the local jurisdictions identify, review, and analyze what they are currently doing to reduce losses, and identify the framework that is in place or should be in place for the implementation of new mitigation actions. The information generated will help the county and municipalities evaluate alternative mitigation actions. Similarly, analyzing what the county and municipalities have the capacity to do, and understanding what needs to be changed or enhanced to facilitate loss reduction, enables all concerned to address shortfalls in the mitigation plan. The capability assessment completed for Onslow County should serve as a planning step and an important part of the foundation for developing effective hazard mitigation strategies.
A basic overall capability assessment is addressed in this section with certain mentions of municipal capabilities. For specific municipal information refer to the respective municipal annex capability assessment.
6.2. Capability Assessment Findings
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The findings of the capability assessment are summarized in this plan to provide insight in Onslow County and participating jurisdictions capacity to implement hazard mitigation activities.
6.2.1. Local Government Legal Authority in North Carolina
Onslow County is a local government body with a Board-Manager form of government. The elected Board of Commissioners is the County’s decision-making body. The appointed Planning Board serves as an advisory body to the elected Board on planning matters. The County has a number of professional staff departments to serve the citizens of the County and to carry out day-to-day administrative activities.
Local regulations, which are enacted within the bounds of the State’s enabling authority, do not automatically meet with judicial acceptance. Any restrictions, which local governments impose on land use or building practices, must follow the procedural requirements of the Fourteenth Amendment, or risk invalidation.
These and other constitutional mandates apply to Federal and State governments and all their political subdivisions. Any mitigation measures that are undertaken by the local government in its regulatory capacity must be worded and enforced carefully within the parameters established by the State and Federal Constitutions, even when such measures are authorized by the General Statutes of North Carolina and even when such measures are enacted in order to protect public health and safety by protecting the community from the impacts of natural hazards.
All local government powers fall into one of four basic groups (although some governmental activities may be classified as more than one type of power): regulation, acquisition, taxation, and spending. Hazard mitigation measures can be carried out under each of the four types of powers.
Regulation Local governments in North Carolina have been granted broad regulatory powers in their jurisdictions. North Carolina General Statutes bestow the general police power on local governments, allowing them to enact and enforce ordinances, which define, prohibit, regulate, or abate acts, omissions, or conditions detrimental to the health, safety, and welfare of the people, and to define and abate nuisances (including public health nuisances). Since hazard mitigation can be included under the police power (as protection of public health, safety, and welfare), towns, cities, and counties may include requirements for hazard mitigation in local ordinances. Local governments may also use their ordinance-making power to abate "nuisances," which could include, by local definition, any activity or condition making people or property more vulnerable to any hazard. Local government enforcement of existing ordinances, building codes, and local plans is critical to effective mitigation.
Acquisition The power of acquisition can be a useful tool for pursuing mitigation goals. Local governments may find the most effective method for completely "hazard-proofing" a particular piece of property or area is to acquire the property (either in fee or a lesser interest, such as an easement), thus removing the property from the private market and eliminating or reducing the possibility of inappropriate development occurring. North Carolina legislation empowers cities, towns, and counties to acquire property for public purpose by gift, grant, devise, bequest, exchange, purchase, lease, or eminent domain.
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Taxation Taxation is yet another power granted to local governments by North Carolina law, which can be used as a hazard mitigation tool. However, the power of taxation extends beyond merely the collection of revenue. Many communities set preferential tax rates for areas, which are unsuitable for development (e.g., agricultural land, wetlands) and can be used to discourage development in hazardous areas.
Local units of government also have the authority to levy special assessments on property owners for all or part of the costs of acquiring, constructing, reconstructing, extending, or otherwise building or improving beach erosion control or flood and hurricane protection works within a designated area. This can serve to increase the cost of building in such areas, thereby discouraging development.
Because the usual methods of apportionment seem mechanical and arbitrary, and because the tax burden on a particular piece of property is often quite large, the major constraint in using special assessments is political. Special assessments seem to offer little in terms of control over land use in developing areas. They can, however, be used to finance the provision of services a county deems necessary within its boundaries. In addition, they are useful in distributing to the new property owners the costs of the infrastructure required by new development.
Expenditure The fourth major power that has been delegated from the North Carolina State General Assembly to local governments is the power to make expenditures in the public interest. Hazard mitigation principles should be made a routine part of all spending decisions made by the local government, including annual budgets and Capital Improvement Plans.
A capital program is usually a timetable by which a county indicates the timing and level of municipal services it intends to provide over a specified duration. Capital programming, by itself, can be used as a growth management technique, with a view to hazard mitigation. By tentatively committing itself to a timetable for the provision of capital to extend municipal services, a community can control its growth to some extent especially where the surrounding area is such that the provision of on-site sewage disposal and water supply are unusually expensive. In addition to formulating a timetable for the provision of services, a local community can regulate the extension of and access to municipal services.
A Capital Improvement Program (CIP) that is coordinated with extension and access policies can provide a significant degree of control over the location and timing of growth. These tools can also influence the cost of growth. If the CIP is effective in directing growth away from environmentally sensitive or high hazard areas, for example, it can reduce environmental costs.
6.2.2. Emergency Management
A comprehensive emergency management program is based on the framework of the five key mission areas of emergency management: prevention/protection, preparedness, mitigation, response, and recovery. All phases are highly interconnected; that is, each phase influences the other three phases. The cycle as a whole is dynamic and ongoing process. Planning in each phase is a critical part of the emergency management program and a key to the successful implementation of hazard mitigation actions. Opportunities to reduce potential losses through mitigation practices are most often implemented before disaster strikes, such as elevation of flood prone
SECTION 6: CAPABILITY ASSESSMENT 3 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 structures or through the continuous enforcement of policies that prevent or regulate development that is vulnerable to hazards because of its location, design or other characteristics. Mitigation opportunities will also be presented during immediate preparedness or response activities (such as installing storm shutters in advance of a hurricane), and certainly during the long‐term recovery and redevelopment process following a hazard event. Figure 6.1 shows the five mission areas of a comprehensive emergency management program.
Figure 6.1: Emergency Management Mission Areas
There are a range of emergency management plans that jurisdictions can utilize to aid in each of the core mission areas. These include:
Hazard Mitigation Plan: The purpose of mitigation planning is to identify policies and actions that can be implemented over the long term to reduce risk and future losses. Mitigation Plans form the foundation for a community's long-term strategy to reduce disaster losses and break the cycle of disaster damage, reconstruction, and repeated damage. The planning process is as important as the plan itself. It creates a framework for risk- based decision making to reduce damages to lives, property, and the economy from future disasters.
Onslow County and the five municipalities of Holly Ridge, Jacksonville, North Topsail Beach, Richlands and Swansboro developed the first version of the multi-jurisdictional plan in 2005 and have maintained and updated the plan on five year FEMA cycle.
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Debris Management Plan: Communities with a debris management plan are better prepared to restore public services and ensure the public health and safety in the aftermath of a disaster, and they are better positioned to receive the full level of assistance available to them from FEMA and other participating entities.The core components of a comprehensive debris management plan incorporate best practices in debris removal, reflect FEMA eligibility criteria, and are tailored to the specific needs and unique circumstances of each applicant.
Onslow County maintains a debris management plan and maintains contracts with a debris monitoring company to assist with management and documentation. The county also maintains a debris hauling contract. Each municipality also maintains debris hauling contracts.
Emergency Operations Plan: An all-hazards plan developed for use by government agencies to ensure a coordinated and effective response to disasters that may occur within its jurisdictional boundaries. The plan is organized to coordinate with the core mission areas of a comprehensive emergency management program.
Onslow County maintains a countywide comprehensive emergency operations plan and manages the central emergency operations center. Each jurisdiction also maintains municipal emergency operations plans to guide specific operations within their jurisdiction and manages municipal emergency operations centers for this purpose. All EOC’s maintain contact and coordination throughout any event through multiple methods including the use of the web based program WebEOC.
Continuity of Operations Plan: Continuity of Operations, as defined in the National Security Presidential Directive-51/Homeland Security Presidential Directive-20 (NSPD-51/HSPD-20) as an effort within individual governmental agencies to ensure that Primary Mission Essential Functions (PMEFs) continue to be performed during a wide range of emergencies, including localized acts of nature, accidents and technological or attack- related emergencies.
Onslow County maintains a continuity of operations plan for all departments.
6.2.3. General Planning
The implementation of hazard mitigation activities often involves individuals other than the emergency management profession. Stakeholders may include local planners, public works officials, economic development specialists and others. Similarly, hazard mitigation planning cuts across multiple disciplines. Some of the most important capabilities that can be utilized for hazard mitigation include comprehensive plans, building codes, floodplain ordinances, subdivision and land development ordinances and zoning ordinances. These tools provide mechanisms for the implementation of adopted mitigation strategies.
Comprehensive or Master Planning: In order to exercise the regulatory powers conferred by the General Statutes, local governments in North Carolina are required to create or designate a planning agency. The planning agency may perform a number of duties, including: make studies of the area; determine objectives; prepare and adopt plans for achieving those objectives; develop and recommend policies, ordinances, and administrative means to implement plans; and perform other related duties. The importance of the planning powers of local governments is emphasized in NC General Statute 160A-383, which requires that zoning regulations be made in accordance with a comprehensive plan. While the ordinance itself may provide evidence that zoning is being conducted in accordance with a plan," the existence of a separate planning document ensures that the government is developing regulations and ordinances that are consistent with the overall goals of the community.
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Subdivision Regulation: Subdivision regulations control the division of land into parcels for building development or sale. F1ood-related subdivision controls typically require that sub-dividers install adequate drainage facilities, and design water and sewer systems to minimize flood damage and contamination. They prohibit the subdivision of land subject to flooding unless flood hazards are overcome through filling or other measures and prohibit filling of floodway areas. They require that subdivision plans be approved prior to the sale of land. Subdivision regulations are a more limited tool than zoning and only indirectly affect the type of use made of land or minimum specifications for structures.
Broad subdivision control enabling authority for municipalities is granted in NC General Statute 160-371. Subdivision is defined as all divisions of a tract or parcel of land into two or more lots and all divisions involving a new street (NC General Statute 160A-376).The definition of subdivision does not include the division of land into parcels greater than 10 acres where no street right-of-way dedication is involved.
Building Codes and Building Inspections: Many structural mitigation measures involve constructing and retrofitting homes, businesses, and other structures according to standards designed to make the buildings more resilient to the impacts of natural hazards. Many of these standards are imposed through the building code.
North Carolina has a State compulsory building code, which applies, throughout the State (NC General Statute143-138). However, municipalities and counties may adopt codes for the respective areas if approved by the State as providing "adequate minimum standards." However, local regulations cannot be less restrictive than the State code.
Local governments in North Carolina are also empowered to carry out building inspection. NC General Statute Ch. l60A, Art. 19, Part 5, and Ch. 153A, Art. 18, Part 4 empower cities and counties to create an inspection department, and enumerates its duties and responsibilities, which include enforcing State and local laws relating to the construction of buildings; installation of plumbing, electrical, heating systems, etc.; building maintenance; and other matters.
Comprehensive Land Use: Regulatory powers granted by the State to local governments are the most basic manner in which a local government can control the use of land within its jurisdiction. Through various land use regulatory powers, a local government can control the amount, timing, density, quality, and location of new development; all these characteristics of growth can determine the level of vulnerability of the community in the event of a natural hazard. Land use regulatory powers include the power to engage in planning, enact and enforce zoning ordinances, floodplain ordinances, and subdivision controls.
The North Carolina Coastal Area Management Act (CAMA) requires each of the 20 coastal counties to have a local land use plan in accordance with guidelines established by the Coastal Resources Commission (CRC). Each CAMA land use plan includes local policies that address growth issues such as the protection of productive resources (i.e., farmland, forest resources, fisheries, etc.), desired types of economic development, natural resource protection and the reduction of storm hazards. At the local level, CAMA land use plans provide guidance for both individual projects and a broad range of policy issues, such as the development of regulatory ordinances and public investment programs.
Onslow County maintains a CAMA plan that includes the Town of Richlands. Holly Ridge, Jacksonville, North Topsail, and Swansboro maintain municipal CAMA Plans.
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Zoning: Zoning is the traditional and nearly ubiquitous tool available to local governments to control the use of land. Broad enabling authority for municipalities in North Carolina to engage in zoning is granted in NC General Statute 160A-381. The statutory purpose for the grant of power is to promote health, safety, morals, or the general welfare of the community. Land uses controlled by zoning include the type of use (e.g., residential, commercial, industrial) as well as minimum specifications for use such as lot size, building height and setbacks, density of population, and the like. The local government is authorized to divide its territorial jurisdiction into districts, and to regulate and restrict the erection, construction, reconstruction, alteration, repair or use of buildings, structures, or land within those districts. Districts may include general use districts, overlay districts, and special use districts or conditional use districts. Zoning ordinances consist of maps and written text.
Historic Preservation Plan: A historic preservation plan is intended to preserve historic structures or districts within a community. An often overlooked aspect of the historic preservation plan is the assessment of buildings and sites located in areas subject to natural hazards, and the identification of ways to reduce future damages. This may involve retrofitting or relocation techniques that account for the need to protect buildings that do not meet current building standards, or are within a historic district that cannot easily be relocated out of harm’s way.
Onslow County maintains a county-wide inventory of historic properties.
Capital Improvements Plan: A capital improvements plan guides the scheduling of spending on public improvements. A capital improvements plan can serve as an important mechanism for guiding future development away from identified hazard areas. Limiting public spending in hazardous areas is one of the most effective long term mitigation actions available to local governments.
Onslow County currently maintains a Capital Improvement Plan.
6.2.3.1. Floodplain Management
Flooding represents the greatest natural hazard facing the nation and the Onslow County planning area. At the same time, the tools available to reduce the impacts associated with flooding are among the most advanced when compared to other hazard-specific mitigation techniques. In addition to approaches that cut across hazards, such as education, outreach, and the training of local officials, the National Flood Insurance Program (NFIP) contains specific regulatory measures that enable government officials to determine where and how growth occurs relative to flood hazards.
In order for a county or municipality to join the NFIP, they must adopt a Local Flood Damage Prevention Ordinance that requires jurisdictions to follow established minimum building standards in the floodplain. Another key service provided by the NFIP is the mapping of identified flood hazard areas. Flood Insurance Rate Maps are used to assess flood hazard risk and set flood insurance rates. The maps also provide an important tool to educate residents, government officials and the business community about the likelihood of flooding in their community. Table 6.1 summarizes NFIP participation in Onslow County.
Table 6.1: NFIP Participation in Onslow County Community Current Effective Policies in Amount of NFIP Entry Date Name Map Force Coverage Holly Ridge 11/03/2005 02/16/2007 45 $ 9,014,000.00 Jacksonville 02/15/1985 02/16/2007 733 $ 196,517,400.00
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North Topsail Beach 07/02/1987 02/16/2007 1308 $ 247,487,100.00 Richlands 07/02/1987 02/16/2007 25 $ 6,344,000.00 Swansboro 10/18/1983 02/16/2007 170 $ 45,623,000.00 Onslow County 07/02/1987 02/16/2007 2087 $ 528,830,100.00 TOTALS: 4368 $ 1,033,815,600.00 The National Flood Insurance Program's (NFIP) Community Rating System (CRS) is a voluntary incentive program that recognizes and encourages community floodplain management activities that exceed the minimum NFIP requirements. As a result, flood insurance premium rates are discounted to reflect the reduced flood risk resulting from the community actions meeting the three goals of the CRS:
Reduce flood damage to insurable property; Strengthen and support the insurance aspects of the NFIP, and Encourage a comprehensive approach to floodplain management.
Table 6.2 Identifies participating CRS communities in Onslow County along with their current class ranking and respective discounts available to homeowners.
Table 6.2: CRS Participating Communities Current % Discount Community CRS Entry Current % Discount Community Name Effective for Status Number Date Class for SFHA Date Non-SFHA 370178 Jacksonville 10/01/1991 10/01/2005 8 10 5 C 370466 North Topsail Beach 10/01/1992 10/01/2002 7 15 5 C
Floodplain Management Plans: A floodplain management plan (or a flood mitigation plan) provides a framework for action regarding the corrective and preventative measures in place to reduce flood‐related impacts.
Onslow County, Holly Ridge, Jacksonville, North Topsail Beach, Richlands and Swansboro maintain floodplain management practices. These may be incorporated as a part of a comprehensive land use plan, floodplain ordinances or designated floodplain management plans.
The North Carolina General Statutes declare that the channel and a portion of the floodplain of all the state's streams will be designated as a floodway, either by the local government or by the State. The legislatively declared purpose of designating these areas as a floodway is to help control floods by preventing obstructions, which inhibit water flow and increase flood height and damage and other losses (both public and private) in flood hazard areas, and to promote the public health, safety, and welfare of citizens of North Carolina in flood hazard areas. To carry out this purpose, local governments are empowered to grant permits for the use of the floodways, including the placement of any artificial obstruction in the floodway. No permit is required for certain uses, including agricultural, wildlife and related uses; ground level uses such as parking areas, rotary aircraft ports; lawns, gardens, golf courses, tennis courts, parks, open space, and similar private and public recreational uses. Existing artificial obstructions in the floodway may not be enlarged or replaced without a permit; local governments are empowered to acquire existing obstructions by purchase, exchange, or condemnation if necessary to avoid flood damages.
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The procedures that are laid out for issuing permits for floodway use require the local government to consider the dangerous effects a proposed artificial obstruction may create by causing water to be backed up or diverted; or the danger that the obstruction will be swept downstream to the injury of others; and by the injury or damage that may occur at the site of the obstruction itself. Local governments are to take into account anticipated development in the near future, which may be adversely affected by the obstruction, as well as existing development.
6.2.4. Institutional Capability
Institutional capability is described as an adequacy of departmental and personal resources for the implementation of mitigation related activities. Administrative capability can be evaluated by determining how mitigation-related activities are assigned to local departments and how adequate the personnel resources are for carrying the activities out. The degree of intergovernmental coordination among departments will also affect administrative capability for the implementation and success of proposed mitigation activities.
Onslow County is a chartered county, which is governed by a Board of Commissioner-Manager form of government. In June 2014, there were 1,183 budgeted full-time County employees. Police, Fire, and Rescue departments play critical roles in both natural hazard mitigation and response. The availability and adequacy of hospitals and health care facilities impacts an area's ability to cope with natural hazards. The following provides a brief description of County facilities and departments.
The County’s Department of Emergency Services includes the Emergency Medical Services/ Volunteer Rescue Service, the Emergency 911 Communications Center, Emergency Management Office, Hazardous Materials Management, and the Volunteer Fire Service. These agencies work together to provide the County’s citizens with complete and unified emergency services during a major incident, natural hazard emergencies, or other unforeseen threats to life and property. The County provides significant financial support for nineteen (19) volunteer fire departments and eight (7) rescue volunteer squads. The County’s system of volunteer fire fighting and rescue is both efficient and effective in handling situations in the County’s unincorporated areas.
Police protection is provided by the County Sheriff's Department, which presently employs approximately 186 people. The Sheriff's department coordinates and cooperates with local military base military police.
Onslow Memorial Hospital, Camp Lejeune Naval Hospital, and the Brynn Marr Behavioral Health Care provide adequate major health care services for County residents. The County Health Department provides clinical and public health services to County residents. The County Environmental Health, Solid Waste, Mosquito and Animal Control Departments contribute to the County's public health efforts through the control of health hazards, nuisances, and private wastewater disposal systems.
All jurisdictions currently indicate they have the available personel internally, through coordination with other agencies, or through contracting out to meet the needs of hazard mitigation implementation.
6.2.5. Technical Capability
Technical capability is described as an adequacy of technical expertise of local government employees or the ability to contract outside resources for this expertise in order to effectively execute mitigation activities. Common examples of skill sets and technical personnel needed for hazard mitigation include: planners with knowledge of land development/management practices, engineers or professionals trained in construction practices related to buildings and/or infrastructure, planners or engineers with an understanding of natural
SECTION 6: CAPABILITY ASSESSMENT 9 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 and/or human caused hazards, emergency managers, floodplain managers, land surveyors, scientists familiar with hazards in the community, staff with the education or expertise to assess community vulnerability to hazards, personnel skilled in geographical information systems, resource development staff or grant writers, and fiscal staff.
GIS: Onslow County operates a geographic information system (GIS) that provides essential information and technology for hazard response and mitigation. The GIS system provides detailed data on property ownership, land use type, and location. GIS allows this information to be displayed visually to assist in hazard mitigation planning. The GIS provides fast access to and processing of detailed data that can be used to assist in deployment of resources before, during, and after a natural disaster. The system also permits data and visual analysis of the impacts of past storm events thereby assisting in planning for mitigation of future natural disasters. Onslow County provides GIS services to all of the municipalities except the City of Jacksonville who maintains their own GIS capability.
State and Federal Assistance: Agencies such as the Federal Emergency Management Association (FEMA) and the North Carolina Division of Emergency Management (NCDEM) have made available numerous implementation manuals and other resource documents. These manuals provide information on mitigation techniques for various hazards, including hurricanes, floods, wildfires, tornadoes and earthquakes. The manuals include information on engineering principles, construction methods, costs and suggestions for how techniques can be financed and implemented. Other Federal agencies such as, the US Army Corps of Engineers and Soil Conservation Service also provide similar services. The North Carolina Division of Emergency Management works in concert with these various Federal agencies to ensure that the State and local governments are prepared to respond to natural disasters. A major effort to improve technical information available to local governments is being undertaken by the State of North Carolina and the Federal Emergency Management Agency.
Emergency Managers: All participating jurisdictions indicated that someone within heir current staffing held the role of emergency manager. Currently, only Onslow County has a dedicated emergency management department with an emergency manager and planning officer.
6.2.6. Fiscal Capability
The ability of a local government ot take action is closely related with the amount of money available to implement policies and projects. This capability may be achieved through local budgets, state/federal and private grant resources, and other associated programs designed to assist local capabilities. The costs associated with policy and project implementation can vary widely. In some instances, policies will be tied directly to staff costs associated with the creation and monitoring of a given program. In other instances, funds may be linked to a project, such as repetitive loss home acquisition, which may require a significant commitment from local, state and federal funding sources.
Local Funds: In the State of North Carolina, property taxes provide the primary source of County revenue. Property taxes are primarily and typically used to finance services that must be available and delivered on a daily basis, such as schools, health and social services, planning, solid waste management, and emergency services. This leaves very little funding, if any, for additional services and projects. Fortunately, State and Federal funds are available to local governments for the development and implementation of hazard mitigation programs.
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Non-Governmental Funds: Another potential source of revenue for local mitigation efforts, are the contribution of non-governmental organizations, such as churches, charities, community relief funds, the Red Cross, hospitals, for-profit businesses, and nonprofit organizations. A variety of these local organizations can be tapped to help carry out local hazard mitigation initiatives.
State and Federal Funds: There are many sources of Federal and State funding available to local governments for implementing hazard mitigation plans. These programs include Hazard Mitigation Grants, Flood Mitigation Assistance Programs, and the Community Development Block Grants.
The Hazard Mitigation Grant Program (HMGP) provides funding for mitigation measures following a Presidential disaster declaration. The HMGP is funded in most part by the Federal government and administered by respective State governments. HMGP funds can be used for such projects as acquisition or relocation, retrofitting, development of local mitigation standards and comprehensive mitigation plans, structural hazard control and the purchase of equipment to improve preparedness and response.
The Flood Mitigation Grant Program (FMAP) is a federally funded program for mitigation assistance to states, communities and individuals for cost-effective measures to reduce or eliminate the long-term risk of flood damage to the built environment and to real property. Unlike the HMGP, FMAP is available to eligible communities on an annual basis. An eligible community must be a participant in the National Flood Insurance Program and must develop a flood mitigation plan. FMAP funds may be used for such projects as elevation and/or dry flood proofing of structures, acquisition of real property, relocation or demolition of structures, and minor structural projects.
The Community Development Block Grant (CDBG) is another source of funding for hazard mitigation initiatives. The objective of the CDBG program is to assist communities in rehabilitating substandard dwelling structures and to expand economic opportunities, primarily for low-to-moderate-income families. However, because of a Presidential declared disaster, CDBG funds may be used for long-term needs such as acquisition, reconstruction, and redevelopment of disaster-affected areas
County Economic Tir Designations: North Carolina contains 100 counties. Every year the Department of Commerce ranks each county based on economic well-being and assigns it to one of three tiers. The 40 most distressed counties are designated as Tier 1, the next 40 are Tier 2 and the 20 least distressed are Tier 3. Onslow County was ranked as Tier 2 in the 2014 designation roster.
Local governments may also engage in their own "fund-raising" efforts to pay for mitigation programs that benefit the community at large. In North Carolina, local governments are granted limited powers to raise revenue for public purpose. The General Assembly (NC General Statute §16A-209) has conferred upon cities, towns, and counties the power to levy property taxes for various purposes, including: ambulance services / rescue squads beach erosion and natural disasters (including shoreline protection, beach erosion control, and flood and hurricane protection) civil defense drainage projects or programs fire protection hospitals
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joint undertakings with other county, city, or political subdivisions planning sewage solid waste water / water resources watershed improvement projects
These statutorily enumerated purposes make it clear that local governments are empowered to finance certain emergency management activities, including mitigation activities, with property taxes.
6.2.7. Political Capability
One of the most difficult and sensitive capabilities to evaluate involves the political will of a jurisdiction to enact meaningful policies and projects. However, having the support of local governing bodies and officials is imperative to the success of any mitigation effort. Political capability in the municipalities in the county varies. Hazard mitigation may not be a local priority, or may conflict with or be seen as an impediment to other goals of the community, such as growth and economic development. Therefore the local political climate must be considered in designing mitigation strategies, as it could be the most difficult hurdle to overcome in accomplishing their adoption and implementation.
Onslow County is working to establish hazard mitigation in its daily operations. In doing this, the County works in close cooperation with the municipalities to prioritize many of the issues surrounding mitigation efforts. In the long run public education and awareness campaigns about the economic efficiency and social utility of mitigation measures helps foster its general acceptance by citizens, and in turn elected officials. Disaster prevention and recovery takes close intra and inter governmental coordination and cooperation between all agencies – local, State, and Federal. This coordination and cooperation is essential in creating a viable and workable local mitigation strategy. Onslow County is politically capable of carrying out this plan and its hazard mitigation goals and objectives.
6.3. Conclusions on Local Capability
After gathering the preceding capability information, the data must be analyzed and evaluated. Since the capability assessment will provide the framework for developing recommendations for specific mitigation actions in the hazard mitigation plan, it is essential that the assessment both identify shortfalls in a jurisdiction's capability, as well as draw attention to special opportunities that should be capitalized upon while they remain viable. Specific Jurisdictional conclusions can be referenced in the respective municipal annex. Overall each jurisdiction participating in this plan has shown a willingness and commitment to hazard mitigation.
The development of the Hazard Mitigation Plan entails reviewing and updating existing land use policies and regulatory ordinances while considering new policies and ordinances that improve and extend protection of the public health, safety, and welfare. The hazard mitigation planning process has provided the opportunity to ensure that all planning efforts work cohesively in order to achieve mitigation goals for existing and future development. Integration into the existing regulatory framework will ensure that the Hazard Mitigation Plan will be utilized to its full potential.
Table 6.3 provides a summary of the County's existing policies and programs and their effectiveness at mitigating natural hazards. Generally, this assessment shows that Onslow County has been committed to
SECTION 6: CAPABILITY ASSESSMENT 12 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 mitigating the effects of natural hazards but in response to recent storm events, additional action may need to be taken. An acceptability assessment is a useful analytical step, which can help Onslow County prioritize and focus limited resources on the most critical of its mitigation needs. Having reviewed which natural hazards pose the greatest threats, the capability of Onslow County to respond, and the particular areas of the County's planning jurisdiction that are most vulnerable, Onslow County can then decide whether this level of risk is acceptable. Local officials and planners can use these conclusions to focus local mitigation efforts on those areas where they are most critically needed, thus making the most of limited financial personnel, and material resources. Conclusions can also help determine whether it is necessary to increase the area's capability in certain areas to reduce its vulnerability.
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Table 6.3: Policy and Program Assessment Policies / Programs
Recommendations for Document/ Effectiveness for Rationale for Policy / Program Status1 Incorporating into Hazard Reference2 Mitigation Effectiveness3 Mitigation Strategy
1. Comprehensive Plan
Onslow County supports State standards for shoreline High, because the stabilization in which the preferred methods are Comprehensive County maintains Continue to support State 1.1 stated as follows: (1) marsh grass or other natural High Plan (pg. 25) standards equivocal to standards protective features (2) sloped riprap and (3) vertical the State. bulkheads (only as last resort).
Onslow County encourages the State of North High, because it limits Continue to encourage the Carolina, as well as all area local governments to the amount of Comprehensive acquisition and development 1.2 diligently pursue the acquisition and development of High structures in the Plan (pg. 26) of waterfront property for waterfront properties for public use, particularly floodplain or storm public use regarding boating access surge location High, because it allows Continue to require the Onslow County will work, whenever possible, to Comprehensive an area for flood waters retention and management 1.3 require the retention and management of natural High Plan (pg. 46) without causing damage of natural buffers along vegetation in buffer areas along its creeks and rivers to property creeks and rivers Onslow County supports NC Division of Water Quality High, because it requires regulations regarding storm water runoff resulting necessary drainage to Continue to require from development activity. Intensive growth and Comprehensive 1.4 High reduce the likelihood of appropriate corrective development will not be allowed where poor drainage Plan (pg. 46) water damage to improvements exists unless appropriate corrective improvements are structures to be completed as part of the project.
Medium, because it Onslow County shall give priority consideration to does not address Address specific goals to Comprehensive 1.5 corrective measures to prevent the flooding of roads, Medium specific mitigation prevent flooding by intense Plan (pg. 46) houses, and businesses caused by intense rain events activities to accomplish rain events this goal SECTION 6: CAPABILITY ASSESSMENT 14 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 Development activities in the 100-year floodplain or Medium, because it near water bodies shall be carefully controlled. If Continue to prefer low Comprehensive prefers low intensity 1.6 development must occur, low intensity uses such as Medium intensity uses in the 100-year Plan (pg. 47) uses in the 100-year recreation and agriculturally related activities floodplain floodplain (adequately buffered) shall be preferred Medium, because it discourages the placement of septic Continue to discourage the Onslow County shall discourage the placement of Comprehensive 1.7 High systems in the placement of septic systems septic systems within the 100-year floodplain Plan (pg. 47) floodplain that could in the 100-year floodplain lead to groundwater contamination High, because it Onslow County supports coordinated efforts to Continue to support efforts supports coordinated preserve and protect the ecological and flood hazard Comprehensive to protect the flood hazard 1.8 High efforts to protect the benefits of freshwater wetlands, as protected under Plan (pg. 64) benefits of freshwater flood hazard benefits of Section 404 of the Clean Water Act of 1972 wetlands freshwater wetlands
2. Flood Damage Prevention Ordinance
High, because it Flood Damage supports improvements Continue to support efforts All new construction and substantial improvements Prevention made to prevent to protect the flood hazard 2.1 shall be anchored to prevent floatation, collapse, or High Ordinance (pg. flotation, collapse, or areas through construction lateral movement of the structure 400) lateral movement of and improvement mitigation structures
High, because it Continue to support Flood Damage All new construction and substantial improvements supports materials and construction and Prevention 2.2 shall be constructed with materials and utility High utility equipment that is improvements made with Ordinance (pg. equipment resistant to flood damage resistant to flood equipment resistant to flood 400) damage damage
Continue to support the Medium, because it Electrical, heating, ventilation, plumbing, air location and design of Flood Damage prevents water from conditioning equipment, and other service facilities service facilities as to Prevention entering or 2.3 shall be designed and located as to prevent water Medium prevent water entering or Ordinance (pg. accumulating within from entering or accumulating within the components accumulating within the 400) service facilities during during conditions of flooding components during conditions of flooding conditions of flooding
SECTION 6: CAPABILITY ASSESSMENT 15 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 High, because it helps to Continue to support new and All new and replacement water supply systems shall Flood Damage prevent floodwater replacement water supply be designed to minimize or eliminate infiltration of Prevention from entering the 2.4 High systems that help maintain a floodwaters into the systems and discharges from the Ordinance (pg. system and discharges high quality of water for systems into floodwaters 400) from entering citizens of Onslow County floodwater High, because it Continue to support new and minimizes or eliminates New and replacement sanitary sewage systems shall Flood Damage replacement sewage systems infiltration of be designed to minimize or eliminate infiltration of Prevention that will help minimize or 2.5 High floodwaters into the floodwaters into the systems and discharges from the Ordinance (pg. eliminate infiltration of sewage systems and systems into floodwater 400) floodwaters into sewage discharges from systems entering the floodwater Medium, because Continue to support disposal Flood Damage disposal systems will On-site waste disposal systems shall be located and systems that are located and Prevention make all possible efforts 2.6 constructed to avoid impairment to them or Medium constructed to prevent Ordinance (pg. to eliminate impairment contamination from them during flooding impairment or 400) or contamination from contamination from flooding flooding Medium, because requiring the base flood Continue to support new New construction or substantial improvement of any Flood Damage elevation to be two feet construction and residential structure shall have the lowest floor Prevention 2.7 Medium may assist in the improvements that have the elevated no lower than two feet above the base flood Ordinance (pg. mitigation of flood lowest floor two feet above elevation 401) damage at lower levels the base flood elevation of structures Elevated buildings that include fully enclosed areas High, because exterior used for the sole purpose of parking vehicles, building Flood Damage walls will allow for the Continue to require elevated access, or storage which is subject to flooding shall be Prevention entry and exit of buildings to have exterior 2.8 High designed to automatically equalize hydrostatic flood Ordinance (pg. floodwaters, thus walls that automatically forces on exterior walls by allowing for the entry and 402) reducing flooding in equalize flood forces exit of floodwaters enclosed areas.
All applicants wishing to purchase a permit for Medium, because upon Flood Damage temporary structures must submit, in writing to the notification, it is the Continue to require a plan Prevention 2.9 local administrator, a plan for the removal of the Medium applicant's responsibility for the removal of Ordinance (pg. structure in the event of a hurricane or flash flood to move the temporary temporary structures 402) notification structure
SECTION 6: CAPABILITY ASSESSMENT 16 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 High, because the Continue to restrict Areas designated as floodways will have no floodway is an encroachments, make encroachments; all new construction and Flood Damage extremely hazardous construction and improvements shall comply with applicable flood Prevention area due to the velocity improvements comply with 2.10 High reduction provisions; and no manufactured homes Ordinance (pg. of waters which carry provisions, and allow shall be permitted, except in an existing manufactured 403) debris, potential manufactured homes only in home park or subdivision projectiles, and has pre-existing mobile home erosion potential parks
1 Potential or Existing Policy/ Program 2 Plan and Page Number 3 Low, because allows for development in the floodplain
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7. MITIGATION STRATEGY
This section of the plan will provide a blueprint for Onslow County to follow to help address and become less vulnerable to the identified hazards. It is based on the findings and conclusions of the Hazard Identification, Risk Assessment and Capability Assessment. This section contains the following subsections:
7.1 Introduction
7.2 Community Goals & Mitigation Objectives
7.3 Identification and Analysis of Mitigation Techniques
7.1. Introduction
A mitigation strategy helps provide Onslow County with a basis for action. Based on the County’s hazard identification, its vulnerability assessment, and its capability assessment the Onslow County Hazard Mitigation Plan Advisory Committee endeavored to develop appropriate and cost effective Hazard Mitigation strategies consistent with the achievement of the stated FEMA and NC State overall Goal: “To substantially reduce loss of life and damage to property” stemming from these events. Onslow County’s Hazard Mitigation Plan was designed to be both comprehensive and strategic in nature. That is, the plan was created to provide a comprehensive review of hazards and identify policies and projects intended to not only reduce the future impacts of hazards, but also assist the county, and participating jurisdictions, to achieve compatible economic, environmental and social goals. The plan is strategic in that all policies are linked to departments or individuals responsible for their implementation. When possible, funding sources that may be used to assist have been identified.
Planning Approach
In order to guide the actions of those charged with implementation the plan follows a traditional planning approach beginning with identification of mitigation goals. The goals are broad statements that set community priorities for reducing susceptibility to natural hazards. They serve as the basis for development of the more specific plan objectives and hazard mitigation activities. They are achieved through more action oriented objectives. The objectives address problems and situations identified through analysis of the hazard profile, vulnerability assessment, and local government capability assessment and are specific to each jurisdiction. Objectives are more tangible and specific than goals. When an objective is accomplished, it may be checked off and progress directed toward accomplishing another objective. Whereas goals are general statements that may never be fully realized, objectives should be capable of being accomplished. Onslow County hazard mitigation objectives provide intermediate steps toward reaching the goals that have been provided in this plan. The objectives include both hazard mitigation policies (such as land use regulations) and hazard mitigation projects that seek to address specifically targeted hazard risks (such as repetitive loss property acquisition).
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The second step involves identification, consideration and analysis of available mitigation measures to help achieve the identified goals. This process is long term and continuous and is sustained through the review, development and maintenance of this Plan. Through this process alternative measures will continue to be considered when future opportunities are identified, data and technology improve, or funding becomes available.
The third step is the selection and prioritization of specific mitigation actions for Onslow County and the participating jurisdictions. The mitigation action plans represent unambiguous and functional plans for action and are considered essential for the mitigation planning process. Actions may include policies or projects designed to reduce the impacts of future hazard events. Mitigation Action Plans will be specific to each jurisdiction in this plan. The jurisdictional mitigation actions and policies can be found in the respective Jurisdictional Annex. The components of the planning framework are explained in greater detail below:
Goals: Goals represent broad statements that are achieved through the implementation of more specific actions. Goals provide the framework for achieving the intent of the plan.
Hazard Mitigation Policies: Policies are defined as a course of action agreed to by members of the team. Funding sources are listed, if applicable.
Hazard Mitigation Projects: Projects are defined as specific actions taken to address defined vulnerabilities to existing buildings are systems.
Mitigation Action Plan: Prioritized listing of actions (policies and projects, including a categorization of technique, individual or organization responsible for completion, and potential funding sources if applicable.
7.2.Community Goals and Mitigation Objectives
Every five-year cycle the Plan Advisory Committee reviews the goals that were identified for the plan. Goals and ELEMENTS C344 CFR Part objectives are addressed at a countywide level and then also 201.6(c)(3)(i): addressed individually at a municipal level. To achieve the The Hazard Mitigation Strategy shall include a description of broad community goals listed above an analysis of those the mitigation goals to reduce goals was conducted resulting in the specific goals listed in. or avoid long-term These goals are intentionally broad in scope and written to vulnerabilities to the identified assist in setting our community priorities, and provide the hazards. basis for the County’s hazard mitigation objectives and implementation strategies included in this plan.
Decrease the community’s vulnerability to future hazard events. Increase the community’s resiliency so that recovery can be quicker and less costly. Decrease the likelihood that a future natural hazard becomes a natural disaster. Ensure that future development contributes to the community’s sustainability over time.
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To enhance local government capability to lessen the impacts of all natural hazards Restore and protect the natural capacity of floodplains to prevent future disasters, improve public health, restore degraded ecosystems, and make communities livable To identify and protect critical services, buildings, facilities and infrastructure that are at risk of damage due to natural hazards and to undertake cost-effective mitigation measures to minimize losses To develop an effective public awareness/ education/ outreach program for natural hazards the County and municipalities are most likely to experience. To protect persons and property, as well as reduce damage and loss to existing community assets. To ensure disaster resistant future development. Minimize the damage to public infrastructure resulting from natural hazards; Manage future development so that vulnerability of private property to natural hazards is reduced; Expedite post disaster reconstruction; Protect the fragile natural and scenic areas located along the New River and its tributaries.
The objectives address problems and situations identified through analysis of the hazard profile, vulnerability assessment, and local government capability assessment and are specific to each jurisdiction. Onslow County hazard mitigation objectives provide intermediate steps toward reaching the goals that have been provided in this plan.
Preserve open space in floodplain areas. Improve education and outreach to the community regarding natural hazards. Provide regulations that effectively mitigate natural hazards and encourage development in suitable areas. Support activities that will make structures less susceptible to damage during natural hazard events. Improve upon the protection of the general population from all natural and man-made hazards. Reduce the potential impact of natural and man-made disasters on OC and local municipalities’ response resources. Reduce the potential impact of natural and man-made disasters on OC and municipal Critical Facilities. Reduce the potential impact of natural and fabricated disasters on the County’s' and municipalities’ infrastructure. Improve Emergency Preparedness.
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Improve the County’s and municipalities’ Disaster Response and Recovery Capability. Reduce the potential impact of natural and man-made disasters on the County’s and municipalities’ economy. Reduce the County’s and municipalities’ liability with respect to natural and man-made hazards generally. Reduce the potential impact of natural and man-made disasters on the County’s and municipalities’ historic places and interests as well as other tangible and intangible characteristics, which add to the quality of life of the County’s and municipalities citizens. 7.3.Identification and Analysis of Mitigation Techniques
The County’s Hazard Mitigation Plan Advisory Committee ELEMENTS C444 CFR Part used the following to develop and prioritize the hazard 201.6(c)(3)(ii): mitigation strategies: Cost-benefit review, Results of Hazard The mitigation strategy shall Identification and Analysis, Results of Vulnerability include a section that identifies Assessment, Results of Community Capability Assessment; and analyzes a comprehensive and Effectiveness in meeting hazard mitigation goals and range of specific mitigation actions and projects being comprehensive plan goals. In order to ensure that a broad considered to reduce the effect range of mitigation actions were considered a comprehensive of each hazard, with particular range of specific mitigation actions for each hazard were emphasis on new and existing analyzed. These fall into the following six broad categories buildings and infrastructure. of mitigation techniques:
7.3.1. Prevention
Preventative activities are intended to keepall hazards problems from getting worse. They are particularly effective in reducing a community’s future vulnerability, especially in areas where development has not occurred or capital improvements have not been substantial. Examples of preventative activities include:
Planning and zoning Hazard mapping Open space preservation Floodplain regulations Stormwater management Drainage system maintenance Capital improvements programming Shoreline / riverine / fault zone setbacks
7.3.2. Property Protection
Property protective measures enable structures to better withstand hazard events, remove structures from hazardous locations, or provide insurance to cover potential losses. Examples include:
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Acquisition Relocation Building elevation Critical facilities protection Retrofitting (i.e., wind proofing, flood proofing, seismic design standards, etc) Insurance Safe room construction
7.3.3. Natural Resource Protection
Natural resource protection activities reduce the impact of hazards by preserving or restoring the function of natural systems. Examples of natural systems that can be classified as high hazard areas include floodplains, wetlands and barrier islands. Thus, natural resource protection can serve the dual purpose of protecting lives and property while enhancing environmental goals such as improved water quality or recreational opportunities. Parks, recreation or conservation agencies and organizations often implement these measures. Examples include:
Floodplain protection Beach and dune preservation Riparian buffers Fire resistant landscaping Erosion and sediment control Wetland restoration Habitat preservation Slope stabilization
7.3.4. Structural Projects
Structural mitigation projects are intended to lessen the impact of hazards by modifying the environment or hardening structures. Structural projects are usually designed by engineers and managed or maintained by public works staff. Examples include:
Reservoirs Levees, dikes, floodwalls, or seawalls Detention and retention basins Channel modification Beach nourishment Storm sewer construction
7.3.5. Emergency Services
Although not typically considered a mitigation technique, emergency services minimize the impact of a hazard on people and property. Actions taken prior to, during, or in response to a hazard event include:
Warning systems
SECTION 7: MITIGATION STRATEGY 5 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
Search and rescue Evacuation planning and management Flood fighting techniques
7.3.6. Public Education and Awareness
Public Information and awareness activities are used to advise residents, business owners, potential property buyers, and visitors about hazards and mitigation techniques they can use to protect themselves and their property. Examples of measures used to educate and inform the public include:
Outreach and education Training Speaker series, demonstration events Real estate disclosure Hazard expositions
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8. MITIGATION ACTION PLAN
The mitigation actions proposed by Onslow County’s local ELEMENTS C544 CFR Part governing body are listed below. The municipal Mitigation 201.6(c)(3)(iii): Strategies and Actions can be found in the respective Annexes The mitigation strategy shall that include: include an action plan describing how the actions Annex 1: City of Jacksonville identified in paragraph (c)(2)(ii) of this section will be Annex 2: Town of Holly Ridge prioritized, implemented, and administered by the local Annex 3: Town of North Topsail Beach jurisdiction.
Annex 4: Town of Richlands
Annex 5: Town of Swansboro ELEMENTS C544 CFR Part 201.6(c)(3)(iv): The Onslow County Mitigation Action Plan lists the action, For multi-jurisdictional plans, there must be identifiable ction the results of the capability assessment, as well as the cost- items specific to the jurisdiction benefit review were given special emphasis, in light of their requesting FEMA approval or possible use in environmental reviews for HMGP, FMA and credit for the plan. other Federal hazard mitigation projects. As a result, each hazard mitigation strategy includes a responsible party for carrying out the implementation, a period by which they should complete the implementation, whether it is new or existing, an implementation status, estimated cost, and other items to demonstrate that each action has been thoroughly assessed for feasibility.
It should be stressed that this plan is a policy document and intended to serve as a planning tool. This plan is not a regulatory document nor does the adoption of the plan require Onslow County to implement all of the objectives included in the plan. However, Onslow County will periodically review their hazard mitigation goa1s; and objectives and make a concerted effort towards implementation.
SECTION 8: MITIGATION ACTION PLAN 1 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
Target Action Responsible Action Hazard Funding Completion Priority Benchmarks / Indicators of Progress # Party Date
PREVENTION
GIS staff will maintain a map and listing of GIS GIS will review the evacuation routes with the P1 streets that will be used for evacuation in Flooding Local Police On-going High Emergency Services Department Director during the event of a hurricane. Fire annual hurricane response training.
Onslow County’s flood plain map will be Flooding GIS Progress will depend on the collaboration between P2 modified prior to the new FEMA flood maps Hurricanes Local On-going Medium PD the State and FEMA being approved. Nor’easter
Control water pollution by regulating point Flooding or PD Monitoring of development sites to ensure storm P3 sources that discharge pollutants into Local On-going Low Discharge State water controls are in place and are maintained. waters in Onslow County. Ensure codes and ordinances are enforced during the Onslow County will rely on its existing permitting and construction processes. Monitor P4 ordinances and land use controls to regulate Flooding Local PD On-going Medium sensitive areas for unpermitted construction development within the floodplain. activities.
Continue to actively pursue State and Federal grant funds to assist in the EM P5 All Grants On-going Medium implementation of the recommendations PD included in this plan.
FEMA and local regulations are reviewed and applied Apply for Community Rating System (CRS) during the building permit and inspection processes. P5 classification and pursue CRS credit points Flooding Local PD On-going High Additionally, progress reports must be submitted to for having this multi-hazard plan in place. FEMA to remain in the program
Adopt a policy prohibiting the development of critical public facilities in the l00-year floodplain in cases where viable alternatives AD P7 exist. Such a policy could be enforced Flooding Local On-going Medium through the County's floodplain and PD subdivision ordinances and permit issuance process.
SECTION 8: MITIGATION ACTION PLAN 2 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 PROPERTY PROTECTION
The Onslow County Geographic Information System’s staff will use flood plain, parcel, Continual software upgrading of GIS is already in and aerial data to map specific flood plain Grants GIS place. Planning will coordinate on an annual basis to PP1 areas. This will allow for future hazard Flooding On-going High Local PD review the floodplain information and notify citizens mitigation community outreach by on an as need basis. educating all citizens on the dangers of living in the flood plain.
Onslow County will continue to support the Flooding Ensure codes and ordinances are enforced during the flood damage prevention codes by enforcing permitting and construction processes. Monitor PP2 Hurricanes Local PD On-going Medium the rules and regulations of new sensitive areas for unpermitted construction construction and maintenance. Nor’easter activities.
Onslow County will continue to support its Flooding Ensure land use recommendations and decisions are storm hazard mitigation policies provided in PP3 Hurricanes Local PD On-going Medium consistent with the goals and policies outlined in the the 1997 Onslow County Coastal Area CAMA Land Use Plan. Management Act (CAMA) Land Use Plan. Nor’easter
Encourage surveyors, engineers, and land planners to become familiar with the NFIP land use and building standards by Provide classes/informational sessions and utilize PP4 distributing copies of the NFIP land use and Flooding Local PD On-going various media platforms to distribute information on building standards from the County's NFIP and Building Code Standards. inspections department when applicants apply for permits
NATURAL RESOURCE ACTION Onslow County shall encourage the long- term management and wise use of its Flooding Ensure land use recommendations and decisions are natural resources including, particularly, Storm NR1 Local PD On-going consistent with the goals and policies outlined in the ocean and estuarine area resources, surface Surge CAMA Land Use Plan. wetland and floodplain ecosystems, and Erosion other important natural areas.
SECTION 8: MITIGATION ACTION PLAN 3 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 Onslow County encourages the prevention of premature conversion of large areas of Maintain Voluntary Ag Districts and overlay districts NR2 productive agricultural land to development All Local PD On-going that protect working lands within Onslow County. and to protect valuable environmental areas from destruction
EMERGENCY SERVICES
Onslow County will continue to educate its Wind FEMA EM Staff will complete training and educational seminars ES1 staff on the HAZUS software endorsed by On-going Medium Flooding Local GIS offered by FEMA. FEMA.
Emergency Management will try to identify An assessment will be conducted at a specified time repetitive loss and severe repetitive loss FEMA EM to evaluate the ability to identify repetitive loss ES2 properties and the Planning Department will Flooding Grants On-going High PD properties and to discuss the funds available to try to obtain funds from grants to remove Local remove the property. these properties.
Wind Onslow County Volunteer Fire Departments The Onslow County Fire Commission will monitor Flooding On-going ES3 will provide additional services during the Local VFD Low progress. Volunteer Fire Departments currently Nor’easter PRN times of emergency/ disasters. provide these services. Hurricanes
The Emergency Operations Plan will be reviewed on Onslow County will continue to support its Local EM ES4 All On-going High an annual basis. Documentation will be provided to Emergency Operations Plan (EOP). Grants BoC NCEM to support these reviews.
Build out of new county wide interoperable P25 Sustain radio communications system Local 800MHz radio system that will include all agencies. ES5 All EM New High through maintenance. Grants System will provide for full interoperability between all agencies during disaster and emergency response. STRUCTURAL Onslow County should pursue the acquisition of properties in at risk areas when they are substantially damaged, meet FEMA Maintain Voluntary Ag Districts and overlay districts S2 the criteria for acquisition, and there is a All Local PD On-Going Medium that protect working lands within Onslow County. planned public re-use for the property. Grants Deed restrictions should be placed on properties that are acquired to prevent SECTION 8: MITIGATION ACTION PLAN 4 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 development.
Onslow County should support the elevation of structures above flood level as an alternative when acquisition is not possible. Emphasis should be placed on structures Local S3 located within the County's Repetitive Loss Flood PD On-Going Medium Areas. All elevations should meet State Grants specifications and prioritization should be based on benefit/ cost rather than flood height.
Flooding The County will continue to maintain a Hurricanes computer database of all structures Nor’easter S4 Local PD On-going Medium Updates to database as projects occur. acquired or elevated through county- Storm sponsored projects Surge Erosion PUBLIC INFORMATION
Onslow County will continue to educate its FEMA Monitoring of the dated educational material will be PI1 citizens on the importance of conserving Drought Grants ONWASA On-Going Medium handled by Planning to ensure that the information water. Local being taught is accurate.
Develop, enhance, and implement education programs aimed at mitigating Local PI2 natural hazards, and reducing the risk to All EM On-Going Medium Grants citizens, public agencies, private property owners, businesses, and schools.
Ensure that the Onslow County website maintains updated documents about flood EM PI3 insurance, flood protection, floodplain All Local On-going Low PD management, and natural and beneficial functions of floodplains.
SECTION 8: MITIGATION ACTION PLAN 5 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 Educate local real estate agents about the Onslow County website’s NFIP and flood hazard information that will advise potential PD PI5 Flood Local On-Going Low buyers to investigate the flood hazard for EM the property they are considering purchasing. Send a flood protection flyer to all properties in the County through a document that that is distributed to all residences. The flyer should include the following information: a general identification of the local flood hazard, flood safety, flood insurance, property protection, Local EM PI6 Flooding On-going Medum floodplain development permit Grants PD requirements, and drainage system maintenance. In addition, the flyer should specifically state that although a particular house may not require flood insurance that does not mean that a garage or outbuilding on the property is not subject to flooding. Provide information on the Onslow County website that explains what you can do to protect your property from wildfires. This PI7 Wildfire Local EM On-going Low should include ways for individuals to stay safe in addition to ways to prevent property loss. Provide material on the Onslow County website regarding the hazards of thunderstorms, lightning, and hailstorms. Severe PI8 This should include danger signs, what kind Thunderstor Local EM On-going Low of disaster supplies would be needed, and m ways to help prevent loss of life and/or property.
Provide brochures on the Onslow County website explaining to residents what to do if PI9 they find a sinkhole on agricultural land, on Sinkhole Local EM On-going Low commercial or industrial sites, or at their residential property
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Establish and maintain a 5 year schedule for Maintain a 5 year schedule to ensure FEMA approval P20 review and updates of the Countywide All Local EM New Medium status is maintained. multi-jurisdictional Hazard Mitigation Plan.
Abbreviations: GIS – Geographical Information Systems PD – Planning Department EM – Emergency Management AD – Administration VFD – Volunteer Fire Department BoC – Board of Commissioners,
SECTION 8: MITIGATION ACTION PLAN 7 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
9. PLAN MAINTENANCE
This section discusses how the Mitigation Strategy and Mitigation Action Plan will be implemented and how the Hazard Mitigation Plan will be evaluated and enhanced over time. This section also discusses how the public will continue to be involved in a sustained hazard mitigation planning process. It consists of the following three subsections:
9.1. – Implementation
9.2 – Monitoring, Evaluating and Updating the Plan
9.3 – Incorporation into Other Planning Mechanisms
9.4 – Continued Public Involvement
9.5 – Plan Adoptions
9.1. Implementation Each jurisdiction participating in the Plan was responsible for implementing specific mitigation actions as prescribed in their locally adopted Mitigation Action Plan. Each action has been assigned to a specific person or local government office in order to increase accountability and the likelihood of implementation. This approach enabled individual jurisdictions to update their mitigation strategy as needed, without altering the broader focus of the County Plan. The separate adoption of locally-specific actions was required so that each jurisdiction was not held responsible for the action(s) of every other jurisdiction involved in the planning process. Whenever possible, a funding source has been identified that may be considered when attempting to implement the action. In addition, an implementation time period, or a specific implementation date, has been assigned in order to assess whether actions are being implemented in a timely fashion. Strategies that will be incorporated into existing programs or activities are identified. Plan implementation will start from the time that it each plan is adopted.
9.2.Monitoring, Evaluating and Updating the Plan
9.2.1. Monitoring ELEMENTS A644 CFR Part After a local hazard mitigation plan has been developed and 201.6(c)(4)(i): The plan shall include a plan adopted, it is important to continually track the progress of maintenance process that mitigation actions and evaluate how the implementation includes a section describing strategies contained in the plan work in practice. Planners the method and schedule of and other local officials involved in hazard mitigation must monitoring, evaluating and monitor the implementation of the plan and evaluate its updating the mitigation plan effectiveness, in order to recommend additional mitigation within a five‐year cycle. actions and make periodic revisions to the plan.
Monitoring and evaluation are the ongoing processes of compiling information on the outcomes resulting from implementation of the hazard mitigation
APPENDIX A: PLANNING DOCUMENTATION 1 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 plan. This process measures progress in achieving goals, objectives, and implementation strategies. Through the monitoring and evaluation process, revisions required to respond to changes in regional and local conditions may be identified. Local conditions are constantly changing. Changes in land use and development affect a variety of infrastructure issues such as potable water, sewer, roads, storm water facilities, and ecological considerations such as water quality. Storms and other natural processes, like coastal and riverine erosion, continually alter a community's hazardous areas. In addition, strong policies and programs should help achieve some of a community's mitigation objectives. Because so many factors will affect the success of mitigation efforts, a planned evaluation of the local mitigation strategy is essential. Evaluation gives an opportunity to enhance the balance between effective mitigation and future growth and economic development.
9.2.2. Evaluating
Periodic evaluations of the Hazard Mitigation Plan will take place as deemed necessary by the Hazard Mitigation Advisory Committee during the annual meeting(s). Evaluations will not only include an investigation of wether mitigation actions were completed, but also an assessment of how effective those actions were in mitigating losses. A review of the qualitative and quantative benefits (or avoided losses) of mitigation activities will support this assessment. Results of the evaluation will then be compared to the goals and objectives established in the plan and decisions will be maderegarding whether sctions should be discontinued or modified in any way in light of new developments. Progress will be documented by the Hazard Mitigation Advisory Committee for use in the next Hazard Mitigation Plan Update.
The evaluation report will include the following:
A review of the goals and objectives– do they address current and expected conditions? A review of any disasters or hazards that occurred during the year. A review of each element or objective of the original plan, including what was accomplished in the previous year. A discussion of why any objectives were not reached or why implementation is behind schedule. Recommendations for new projects or revised objectives. Has the nature or magnitude of risks changed? Are the current resources appropriate for implementing the plan? Are there implementation problems, such as technical, political, legal or coordination issues with other agencies? Have the outcomes occurred as expected? Did the agencies and other partners participate in the plan and planning process as proposed?
9.2.3. Revisions and Updates
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Periodic evaluation and revision of the plan helps to ensure that local mitigation efforts include the latest and most effective mitigation techniques. Periodic revisions help keep the County and municipal plans in compliance with Federal and State statutes and regulations. Additional development, implementation of mitigation efforts, development of new mitigation processes, and changes in Federal and State statutes and regulations may all affect the local hazard mitigation plan. In the context of a Federal disaster declaration, State and local governments are allowed to update or expand an existing plan to reflect circumstances arising out of the disaster. An updated plan in this circumstance might include a re-evaluation of the hazards and the jurisdiction’s exposure to them, a re-assessment of existing mitigation capabilities, and new or additional mitigation recommendations.
Updates to the OC MJ-HMP will be considered on a 5-year cycle. Each Five Year update will be lead by a representative from Onslow County Emergency Services. The plan review should include recommendations and information gathered by the evaluation process described above and any changes or amendments as determined by the process of annual review described below. Although the comprehensive review and revision is scheduled, some amendments to the Plan may be prompted by a number of circumstances, including identification of specific new mitigation projects, completion of several proposed mitigation actions, or if required to qualify for specific funding.
The review process shall be the responsibility of the OC Hazard Mitigation Plan Advisory Committee and shall consist of the convening of appropriate Plan contributors and/ or meetings with contributors individually as practical or necessary following a disaster or other instances warranting re-examination of the mitigation policies. Meetings will be recorded, should be made public, and such recommendations as may be forthcoming shall be evaluated and forwarded to the overall OC Hazard Mitigation Plan Advisory Committee for consideration and comment.
Each jurisdiction will produce a progress report with recommendations for updates and revision and bring it before their Commissioners or Councils. These reports should reflect updates on progress of mitigation actions, completion of mitigation actions, possible changes in or new areas of funding, and any legislative changes having direct effect on the plan. Progress reports may contain information provided by other reports including, but not limited to, Community Assistance Visits (CAV). As updates occur, the date, reason and responsible party should be noted. Updates or revisions, which affect the plan as a whole or impact any other jurisdiction(s), will require a presentation of findings and recommendations be submitted to those jurisdictions’ council members for adoption.
9.2.4. Procedure for Amending the Hazard Mitigation Plan
A. Initiation of Amendments
Any person or organization, including the Planning Department, may petition the Board of Commissioners to amend this plan. The petition shall be filed with the Planning Department and shall include a description of the proposed text or map amendment, along with an explanation of the changing circumstances that necessitate consideration of the amendment.
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Upon initiation of a text or map amendment, the Planning Department shall forward the proposed amendment to all interested parties, including, but not limited to, all affected County departments, and other interested agencies such as the NC Division of Emergency Management, the US Army Corps of Engineers, and the US Department of Agriculture Natural Resource Conservation Service (USDA NRCS) for a 30-day review and comment period. At the end of the comment period, the proposed amendment shall be forwarded along with all review comments to the Planning Board for its consideration. If no comments are received from the reviewing department or agency within the specified review period, such shall be noted in the Planning Department’s recommendation to the Planning Board.
B. Planning Board Review and Recommendation
The Planning Board shall review the proposed amendment, along with the Planning Department’s recommendation and any comments received from other departments and agencies. The Planning Board shall submit its recommendation on the proposed amendment to the Board of Commissioners within forty-five (45) days. Failure of the Planning Board to submit its recommendation within this period shall constitute a favorable recommendation.
C. Public Hearing Requirements
No amendment to the plan may be adopted until a public hearing has been held. Upon receipt of a recommendation from the Planning Board, the Planning Department shall, after consultation with the Clerk to the Board, schedule a public hearing before the Board of Commissioners on the petition.
The public notice shall be published one (1) time in a newspaper having general circulation within the County at least ten days prior to the scheduled public hearing date. In computing this period, the date of publication shall not be counted but the date of the public hearing shall be.
With respect to map amendments, the Planning Department shall provide first-class mail notice of the public hearing to: Owners, according to County tax records, of all properties whose use of land may be affected by the proposed amendment; and Owners, according to County tax records, of all properties within 100 feet of the properties affected by the proposed amendment.
The Planning Department may also post notices of the public hearing in the vicinity of the properties affected by the proposed amendment and take any other action deemed by the Planning Department to be useful or appropriate to give notice of the public hearing. The notice required or authorized by this section shall:
1. State the date, time, and place of the public hearing;
2. Summarize the nature and character of the proposed change;
3. If the proposed amendment involves a change in potential use of the land, reasonably identify the property whose potential land use would be affected by the amendment;
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4. State that the full text of the amendment can be obtained from the County Planning Department; and
5. State that substantial change in the proposed amendment may be made following the public hearing.
D. Board of Commissioners Review and Adoption
Upon receipt of a recommendation from the Planning Board, the Planning Department shall schedule a public hearing before the Board of Commissioners on the petition according to the procedure outlined in Section “Public Hearing Requirements.”
9.3.Incorporation into Other Planning Mechanisms
The municipal governments have created and incorporated the requirements of the OC MJ-HMP into other County and local ELEMENTS A444 CFR Part plans. The County and municipal planners will incorporate 201.6(b)(3): the requirements of this HMP in updates to local planning The plan maintenance process documents, such as the comprehensive EOP, CAMA land-use shall include a process by which plan, capital improvement plans, and other plans as necessary local governments incorporate the requirements of the and applicable, and those ordinances such as floodplain, sub- mitigation plan into other division, and zoning. The County and municipal planners planning mechanisms such as will provide copies of this plan to each planning advisory comprehensive or capital member as needed. The local planner will recommend to the improvement plans, when advisory committee members to ensure that all goals and appropriate. strategies of new and updated local planning documents are consistent with the hazard mitigation plan and will not contribute to increased vulnerability to the impacts of natural hazards in the jurisdiction.
Onslow County is experiencing a great deal of residential growth throughout the county and considerable commercial growth in the Sneads Ferry area. The county has completed countywide zoning. The Subdivision and Zoning Ordinances address the suitability of land for development, protect property values and natural resources, and minimize hazards. The Flood Damage Prevention Ordinance establishes a two-foot freeboard and also limits development within flood hazard areas. The County enforces the North Carolina Building Code which includes provisions for high wind zone areas. The Joint Land Use Study (JLUS) is complete and we anticipate working with Marine Corps Base Camp Lejeune on the implementation of this study over the next several months.
9.4.Continued Public Involvement ELEMENTS A544 CFR Part In developing the plan, the County sought to educate the 201.6(c)(4)(iii): public by soliciting public participation in the planning The plan maintenance process process and to integrate any proposed new policies and shall include a discussion on ordinances into the County’s existing regulatory environment. how the community will Public meetings were scheduled throughout the planning continue public participation in process to gain valuable citizen input and to broaden public the plan maintenance process.
APPENDIX A: PLANNING DOCUMENTATION 5 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015 understanding and support for development and implementation of the Plan. The Plan was used as an educational tool to convey to County citizens the danger of natural hazards and to outline strategies for mitigating potential damage to lives and property within the County.
A major goal of the hazard mitigation process is to continue to offer support and information to County residents. After adoption of the Plan, the Hazard Mitigation Plan Advisory Committee will play the lead role in seeking to educate citizens on the findings and strategies of the Plan.
Public participation in the OC MJ-HMP is critical to developing a viable HMP. The public is welcomed and encouraged to become actively involved in providing input to the OC Hazard Mitigation Plan Advisory Committee. To facilitate continued public involvement in the planning process:
The public will be invited to participate in the annual review of the plan.
Public notice of plan reviews will be issued via area newspapers, television, pubic notices, and the County’s website.
Copies of the plan will be kept on hand at all public libraries and at appropriate agencies through the County, Cities, and Towns. The plan will have a contact address, email address, and phone number of the person responsible for keeping track of public comments on the plan.
The plan will be available on the Onslow County Website and will contain an email address and phone number the public can use for submitting comments and concerns about the plan.
9.5.Plan Adoptions
At the completion of the planning process, the OC Hazard Mitigation Plan Update Advisory Committee produced a OC Multi-Jurisdiction Hazard Mitigation Plan for submission to the appropriate County and Municipal leaderships for adoption, promulgation, and execution. The County and municipal annexes were adopted and predicated upon final approval by the appropriate State and Federal approving agencies.
Adoption of the OC MJ-HMP follows in accordance with those legal guidelines and statutes, to include The Disaster Mitigation Act 2000; 44 CFR 201.6 (c)(5), that are the process for official adoption. JURISDICTION ADOPTION DATE Town of Holly Ridge Pending FEMA Approval City of Jacksonville Pending FEMA Approval Town of North Topsail Beach Pending FEMA Approval Town of Richlands Pending FEMA Approval Town of Swansboro Pending FEMA Approval Onslow County Pending FEMA Approval
APPENDIX A: PLANNING DOCUMENTATION 6 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
9.5.1. Adoption Resolutions
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APPENDIX A: PLANNING DOCUMENTATION
MEDIA RELEASE Contact: Todd W. Lyman Public Information Officer [email protected] (910) 347-4717 Or Norman Bryson, Emergency Services (910) 347-4270 [email protected] FOR IMMEDIATE RELEASE August 29, 2014
Public Invited to Assist With County Hazard Mitigation Plan Update
Onslow County, NC – Onslow County citizens are invited to attend a public meeting at the Onslow County Emergency Operations Center, 1180 Commons Drive North Sept. 5 from 6-7 p.m. to learn about and contribute to changes to the Onslow County Multi-Jurisdiction Hazard Mitigation Plan. Onslow County Emergency Services plans for weather and environmental hazards resident in our county. This year officials will conduct a mandated five-year update to the hazard mitigation plan. Topics include flood plains, dam and sinkhole risk mitigation, which can impact homeowners and builders here. In 2000, the Federal Disaster Mitigation Act, an amendment of the Robert T. Stafford Disaster Relief and Emergency Assistance Act, was passed and required state and local governments to develop hazard mitigation plans. The plan, at its core, is a living document aimed at reducing the risk and vulnerability of community life and property. The plan also helps increase public awareness of what hazards may affect them and what reduction measures are used in the community. The Onslow County Multi-Jurisdiction Plan identifies all hazards that may affect our area and outlines strategies and policies to reduce vulnerability. FEMA mandates that the hazard mitigation plans be reviewed and updated to ensure that it remains an active and open document. Onslow County has been working with local towns and cities for more than eight months to update their annexes to the multi-jurisdiction plan as part of a scheduled five year review. The document is a draft pending approval by the Onslow County Board of Commissioners prior to state and federal approval. The draft document will be available for review at the meeting. Citizens are encouraged to attend this meeting, which also fulfills one of the FEMA planning requirements. For more information please call 910-347-4270. The plan can be viewed at http://onslowcountync.gov/Departments/Emergency_Services/Hazard_Mitigation/
APPENDIX A: PLANNING DOCUMENTATION 1 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
ONLINE NOTIFICATION
Norman Bryson, Emergency Services (910) 347-4270 [email protected]
Posted at: http://onslowcountync.gov/Departments/Emergency_Services/Hazard_Mitigation/
Onslow County Multi-Jurisdictional Hazard Mitigation Plan Update Information
Mitigation planning is most effective when it is based on a comprehensive, long-term plan that is developed before a disaster occurs. The purpose of mitigation planning is to identify local policies and actions that can be implemented over the long term to reduce risk and future losses from hazards. Local hazard mitigation planning should be community oriented in assessing risk and vulnerability and practices to best minimize or manage those risks. The plan should also establish a maintenance schedule to will ensure it remains current and dynamic and can be incorporated into routine local decision making. Onslow County adheres to the FEMA 5 year review cycle. The next FEMA review is scheduled for 2015.
*** Hazard Mitigation Plan Update Community Meeting***
There will be a public meeting to review and discuss the 2015 proposed Onslow County Multi- Jurisdictional Hazard Mitigation Plan. The plan addresses natural hazards that could potentially affect Onslow County and the municipalities of Holly Ridge, Jacksonville, North Topsail Beach, Richlands, and Swansboro. Citizens are invited to come and review and provide feedback on the plan.
September 5, 2014 6-7pm 1180 Commons Dr. N Jacksonville, NC
For more information please contact Onslow County Emergency Services at 910-347-4270
APPENDIX A: PLANNING DOCUMENTATION 2 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
1st MEETING ATTENDANCE
APPENDIX A: PLANNING DOCUMENTATION 3 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
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3rd MEETING ATTENDANCE
APPENDIX A: PLANNING DOCUMENTATION 5 ONSLOW COUNTY MULTI-JURISDICTIONAL HAZARD MITIGATION PLAN JULY 2015
APPENDIX B: FEMA LOCAL MITIGATION PLAN REVIEW
APPENDIX B: LOCAL MITIGATION PLAN REVIEW 1